JP2019091700A - Compact mass spectrometer - Google Patents

Abstract

A compact and portable mass spectrometer is provided.
A mass spectrometer includes an ion source, an ion trap, an ion detector, and a gas pressure control subsystem. During operation of mass spectrometer 100, gas pressure regulation subsystem 120 is configured to maintain a gas pressure between 100 mTorr and 100 Torr in at least two of ion source 102, ion trap 104, and ion detector 118. The ion detector 118 is configured to detect the ions generated by the ion source 102 according to the mass to charge ratio of the ions.
[Selected figure] Figure 1E

Description

  The present disclosure relates to the identification of substances using mass spectrometry.

  Mass spectrometers are widely used to detect chemicals. In a typical mass spectrometer, molecules or particles are excited or ionized, and these excited species often decompose to form smaller mass ions or react with other species to form other characteristic ions Do. This ion formation pattern can be interpreted by the system operator to infer the identity of the compound.

  In general, in a first aspect, the present disclosure provides a mass spectrometer comprising an ion source, an ion trap, an ion detector, and a gas pressure control subsystem, said gas analyzer operating in said mass spectrometer. The pressure regulation system is configured to maintain a gas pressure between 100 mTorr and 100 Torr in at least two of the ion source, the ion trap, and the ion detector, the ion detector comprising the ion source. The ions generated by the sensor are detected according to the mass to charge ratio of the ions.

  Embodiments of the mass spectrometer may include one or more of the following features.

  In operation, the gas pressure regulation system can be configured to maintain a gas pressure between 100 mTorr and 100 Torr in the ion trap and the ion detector. In operation, the gas pressure regulation system may be configured to maintain a gas pressure between 100 mTorr and 100 Torr in the ion source and the ion trap. In operation, the gas pressure regulation system can be configured to maintain a gas pressure between 100 mTorr and 100 Torr at the ion source and the ion detector. In operation, the gas pressure regulation system can be configured to maintain a gas pressure between 100 mTorr and 100 Torr in the ion source, the ion trap, and the ion detector.

  The ion source can include a glow discharge ionization source. The ion source can include a capacitor discharge ionization source. The ion source can include a dielectric barrier discharge ionization source.

  The gas pressure regulation system may include a gas pump configured to control the gas pressure in the at least two of the ion source, the ion trap, and the ion detector. The mass spectrometer may include a controller that operates the gas pump to control the gas pressure in the at least two of the ion source, the ion trap, and the ion detector. The gas pump can include a scroll pump.

  In operation, the gas pressure regulation system may be configured to maintain a gas pressure between 500 mTorr and 10 Torr in the at least two of the ion source, the ion trap, and the ion detector. In operation, the gas pressure regulation system may be configured to maintain a gas pressure with a difference of less than 10 Torr in at least two of the ion source, the ion trap, and the ion detector. In operation, the gas pressure regulation system may be configured to maintain a gas pressure at the ion source, the ion trap, and the ion detector with a difference less than 10 Torr. In operation, the gas pressure regulation system can be configured to maintain the same gas pressure in at least two of the ion source, the ion trap, and the ion detector. In operation, the gas pressure regulation system can be configured to maintain the same gas pressure in the ion source, the ion trap, and the ion detector.

  The mass spectrometer is a gas path, a gas path to which the ion source, the ion trap, and the ion detector are connected, and a gas inlet connected to the gas path. Gas particles to be analyzed are introduced into the gas path via the gas inlet and the pressure of the gas particles to be analyzed in the gas path is configured to be between 100 mTorr and 100 Torr. And a gas inlet. The gas inlet may be configured such that in operation, a mixture of gas particles comprising the analyzed gas particles and atmospheric gas particles is drawn into the gas inlet, the mixture of gas particles being in the gas path It is not filtered to remove atmospheric gas particles before being introduced.

  The mass spectrometer further comprises a sample gas inlet connected to the gas path, and a buffer gas inlet connected to the gas path, the gas particles being analyzed during operation of the mass spectrometer: The gas gas introduced into the gas path through the sample gas inlet; buffer gas particles are introduced into the gas path through the buffer gas inlet; and the analyzed gas particles in the gas path and the buffer The sample gas inlet and the buffer gas inlet are configured such that the combined pressure with the gas particles is between 100 mTorr and 100 Torr. The buffer gas particles may include nitrogen molecules and / or noble gas molecules.

  The ion source and the ion trap may be enclosed in a housing including a first plurality of electrodes, and the mass spectrometer is configured to releasably engage the first plurality of electrodes. It further comprises a support base with a plurality of electrodes, said housing being repeatedly connectable to said support base and separable from said support base. The mass spectrometer may include an attachment mechanism configured to secure the housing to the support base when the first plurality of electrodes engage the second plurality of electrodes. The attachment mechanism includes at least one of a clamp and a cam.

  The first plurality of electrodes can include a pin, and the second plurality of electrodes can include a socket configured to receive the pin.

  The ion detector can be enclosed within the housing. The gas pressure control system may include a pump, which may be enclosed within the housing.

  The support base includes a voltage source coupled to the second plurality of electrodes, and a controller connected to the voltage source, the controller being configured to connect the ion source when the housing is connected to the support base. And the ion trap. In operation, the controller determines the gas pressure in the at least one of the ion source, the ion trap, and the ion detector, and controls the gas pressure by operating the gas pressure regulation system. It can be configured.

  The largest dimension of the mass spectrometer may be less than 35 cm. The total mass of the mass spectrometer can be less than 4.5 kg.

  The mass spectrometer embodiments can include any of the other features disclosed herein, as appropriate, in any combination.

  In another aspect, the present disclosure includes maintaining a gas pressure between 100 mTorr and 100 Torr in at least two of a mass spectrometer ion source, an ion trap, and an ion detector; and generating by the ion source Detecting the ions according to the mass-to-charge ratio of the ions.

  Embodiments of the method can include one or more of the following features.

  The method can include maintaining a gas pressure between 100 mTorr and 100 Torr at the ion trap and the ion detector. The method can include maintaining a gas pressure between 100 mTorr and 100 Torr at the ion source and the ion trap. The method can include maintaining a gas pressure between 100 mTorr and 100 Torr at the ion source and the ion detector. The method can include maintaining a gas pressure between 100 mTorr and 100 Torr at the ion source, the ion trap, and the ion detector. The method can include maintaining a gas pressure between 500 mTorr and 10 Torr in the at least two of the ion source, the ion trap, and the ion detector. The method can include maintaining a gas pressure at a difference of less than 10 Torr in at least two of the ion source, the ion trap, and the ion detector. The method can include maintaining a gas pressure at the ion source, the ion trap, and the ion detector with a difference of less than 10 Torr. The method may further include maintaining the same gas pressure in at least two of the ion source, the ion trap, and the ion detector. The method may further include maintaining the same gas pressure in the ion source, the ion trap, and the ion detector.

  The method is a step of introducing a gas particle to be analyzed into a gas path connecting the ion source, the ion trap, and the ion detector through a gas inlet, and in the gas path. The pressure of said analyzed gas particles of may comprise between 100 mTorr and 100 Torr. The method can include introducing a mixture of gas particles into a gas path connecting the ion source, the ion trap, and the ion detector via a gas inlet, the gas particles The mixture of A and B includes gas particles to be analyzed and atmospheric gas particles, and the mixture of gas particles is not filtered to remove atmospheric gas particles before being introduced into the gas path.

  The method comprises the steps of: introducing a gas particle to be analyzed into a gas path connecting the ion source, the ion trap, and the ion detector via a sample gas inlet; and buffer gas particles. Introducing through the buffer gas inlet into the gas path, wherein the combined pressure of said analyzed gas particles in said gas path and said buffer gas particles is between 100 mTorr and 100 Torr. It is. The buffer gas particles may include nitrogen molecules and / or noble gas molecules.

  Embodiments of the method can include any of the other features disclosed herein, as appropriate, in any combination.

  In a further aspect, the present disclosure provides a mass spectrometer comprising a support base featuring a first plurality of electrodes and a pluggable module featuring a second plurality of electrodes, the pluggable module comprising: The releasable connection to the support base by engaging the second plurality of electrodes with the first plurality of electrodes, the pluggable module including an ion trap connected to a gas path Including.

  Embodiments of the mass spectrometer may include one or more of the following features.

  The pluggable module can include an ion trap connected to the gas path. The second plurality of electrodes can include a pin, and the first plurality of electrodes can include a socket configured to receive the pin.

  The support base includes a first attachment mechanism, and the pluggable module includes a second attachment mechanism configured to engage the first attachment mechanism.

  The first and second attachment mechanisms may be configured to releasably connect the pluggable module to the support base in only one orientation. One of the first and second attachment mechanisms may include an asymmetrical extension member, and the other of the first and second attachment mechanisms may include a recess configured to receive the extension member. it can. At least one of the first and second attachment mechanisms may include a soft sealing member. At least one of the first and second attachment mechanisms may include at least one of a clamp and a cam.

  The mass spectrometer may include a sample gas inlet connected to the gas path. The mass spectrometer can include an ion detector attached to the support base. The pluggable module can include an ion detector connected to the gas path. The ion detector may be disposed on the support base such that the ion detector is connected to the gas path when the pluggable module is attached to the support base.

  The mass spectrometer can include a pump attached to the support base. The pluggable module can include a pump connected to the gas path. The pump may be disposed on the support base such that the pump is connected to the gas path when the pluggable module is attached to the support base. The pump can include a scroll pump.

  The ion source can include a glow discharge ionization source and / or a capacitor discharge ionization source.

  The mass spectrometer may include an ion detector connected to the gas path, and a controller attached to the support base and connected to the ion trap. During operation of the mass spectrometer, the controller detects ions generated by the ion source using the detector, identifies information related to the identity of the detected ions, and uses an output interface Can be configured to display that information.

  The mass spectrometer may include a pump connected to the gas path and configured to maintain the pressure of the gas particles in the range of 100 mTorr to 100 Torr. The mass spectrometer may include a controller connected to the ion trap and the pump, and in operation of the mass spectrometer, the controller determines a pressure of gas particles in the gas path, the gas particles The pump may be configured to operate to maintain the pressure in the range 100 mTorr to 100 Torr.

  The pump may be configured to maintain the pressure of the gas particles in the range of 100 mTorr to 100 Torr.

  The mass spectrometer may include an enclosure enclosing the support base and the pluggable module, the enclosure comprising an opening disposed adjacent to the pluggable module, the mass spectrometer The user can connect and disconnect the pluggable module to the support base through the opening. The mass spectrometer may include a cover member that, when deployed, closes the opening of the enclosure. The cover member may include a retractable door. The cover member may include a lid that is completely removable from the enclosure.

  The largest dimension of the mass spectrometer may be less than 35 cm. The total mass of the mass spectrometer can be less than 4.5 kg.

  The mass spectrometer embodiments can include any of the other features disclosed herein, as appropriate, in any combination.

  In another aspect, the present disclosure provides a mass spectrometer system comprising any of the mass spectrometers disclosed herein, the mass spectrometer comprising: a first pluggable module; one or more An additional pluggable module is provided, each of the additional pluggable modules includes an ion trap and a third plurality of electrodes, and the additional pluggable module includes the third plurality of electrodes. Engaging with the first plurality of electrodes is configured to releasably connect to the support base.

  Embodiments of the system can include one or more of the following features.

  At least one of the additional plugging modules may include an ion trap substantially similar to the ion trap of the first pluggable module.

  The first pluggable module may comprise an ion source, and at least one of the additional plug-in modules comprises an ion source different from the ion source of the first pluggable module it can. For example, the ion source of the first pluggable module can include a glow discharge ionization source, and at least one of the additional plug-in modules is an ionization source different from the glow discharge ionization source (eg, (Electrospray ionization source, dielectric barrier discharge ionization source, and / or capacitor discharge ionization source) can be included.

  At least one of the additional plug-in modules may comprise an ion trap different from the ion trap of the first pluggable module. The diameter of the ion trap of the first plugging module may be different from the diameter of at least one ion trap of the additional pluggable module. Alternatively or additionally, the cross-sectional shape of the ion trap of the first plug-in module may differ from the cross-sectional shape of the at least one ion trap of the additional pluggable module.

  The first pluggable module can include an ion detector, and each of the additional plugging modules can include an ion detector, and the ion detector of the first plugging module May be different from the ion detector of at least one of the additional pluggable modules.

  At least one surface of the first pluggable module may include a first coating, and at least one surface of the additional plug-in module may have a second coating different from the first coating. Can be included.

  Embodiments of the system can include any of the other features disclosed herein, in any combination, as appropriate.

  In a further aspect, the present disclosure is a mass spectrometer comprising a support base, an ion source attached to the support base, an ion trap attached to the support base, and an ion detection attached to the support base. And a power source attached to the support base, the power source including the ion source, the ion trap, and the power source electrically connected to the ion detector through the support base. The power supply is configured to supply power to the ion source, the ion trap, and the ion detector, when operating the mass spectrometer.

  Embodiments of the mass spectrometer may include one or more of the following features.

  The largest dimension of the mass spectrometer may be less than 35 cm. The total mass of the mass spectrometer can be less than 4.5 kg.

  The mass spectrometer may include a gas pressure regulation system attached to the support base and electrically connected to the power supply via the support base, the power supply operating in the mass spectrometer operation, Electrical power is configured to be supplied to the gas pressure regulation system. The mass spectrometer is a controller attached to the support base, and electrically connects the ion source, the ion trap, the ion detector, and the gas pressure control system via the support base. It can include a connected controller. The ion source, the ion trap, and the ion detector may be connected to a gas path, and when the mass spectrometer is in operation, the gas pressure control system may have a gas pressure in the gas path ranging from 100 mTorr to 100 Torr. (E.g., in the range of 500 mTorr to 10 torr). The gas pressure control system may include a scroll pump.

  The support base can include a printed circuit board.

  The mass spectrometer may include a gas inlet connected to the gas path, the gas inlet including a gas particle to be analyzed and an atmospheric gas particle during operation of the mass spectrometer. A mixture of particles is adapted to be drawn into the gas inlet via the gas inlet, the mixture of gas particles being introduced into the gas path without filtering the atmospheric gas particles. The gas inlet may include a valve electrically connected to the controller, and, in operation of the mass spectrometer, the controller may include a mixture of gas particles for at least 30 seconds. To introduce the gas into the gas path.

  During operation of the mass spectrometer, the controller is configured to detect ions generated by the ion source using the ion detector and to adjust a duty cycle of the ion source based on the detected ions. it can. The controller may be configured to adjust the duty cycle of the ion source by adjusting a time interval at which the ion source generates ions. The controller may be configured to adjust the duty cycle of the ion source by adjusting at least one of the duration and magnitude of the potential applied to an electrode of the ion source.

  During operation of the mass spectrometer, the controller can be configured to identify information related to the identity of the detected ions and display the information using an output interface.

  The ion source can include a glow discharge ionization source and / or a dielectric barrier discharge ionization source.

  The mass spectrometer embodiments can include any of the other features disclosed herein, as appropriate, in any combination.

  In another aspect, the present disclosure is a mass spectrometer comprising an ion source, an ion trap, a detector connected to a gas path, and a gas inlet connected to the gas path and equipped with a valve. Providing a mass spectrometer including a pressure regulation system configured to control gas pressure in the gas path; and a controller connected to the valve, the ion source, the ion trap, and the detector. During operation of the mass spectrometer, the pressure regulation system is configured to maintain a gas pressure above 100 mTorr in the gas path, and the controller is configured to: (a) a mixture of gas particles in the gas path The valve is actuated to be introduced into the chamber, wherein the mixture comprises the gas particles to be analyzed and atmospheric gas particles, and the mixture of gas particles comprises the atmospheric gas particles. Introduced into the gas path without error, the controller (b) activating the ion source to generate ions from the analyzed gas particles, and the controller (c) activating the detector And detecting the ions according to the mass to charge ratio of the ions.

  Embodiments of the mass spectrometer may include one or more of the following features.

  The atmospheric gas particles may include at least one of nitrogen molecules and oxygen molecules. The pressure regulation system may be configured to maintain a gas pressure in the gas path of greater than 500 mTorr (e.g., 1 Torr). The controller may be configured to actuate the valve to continuously introduce the mixture of gas particles into the gas path for at least 10 seconds (at least 30 seconds, at least 1 minute, at least 2 minutes).

  The mass spectrometer comprises: a housing surrounding the ion source and the ion trap, the housing comprising the ion source and a first plurality of electrodes connected to the ion trap; and the first plurality of electrodes. And a support base with a second plurality of electrodes configured to mate, the housing forming a pluggable module configured to releasably connect to the support base. The controller is connectable to the support base.

  The largest dimension of the mass spectrometer may be less than 35 cm. The total mass of the mass spectrometer can be less than 4.5 kg.

  In operation, the controller may be configured to adjust the duty cycle of the ion source based on the detected ions. For example, the controller generates the ions from the gas particle analyzed for a continuous period of 10 seconds or more (e.g., a continuous period of 30 seconds or more, a continuous period of 1 minute or more, a continuous period of 2 minutes or more) The ion source can be configured to be adjusted, as described.

  The mass spectrometer embodiments can include any of the other features disclosed herein, as appropriate, in any combination.

  In a further aspect, the present disclosure includes: introducing a mixture of gas particles into a gas path of a mass spectrometer, wherein the mixture of gas particles comprises a gas particle to be analyzed and an atmospheric gas particle, said gas particle A mixture of (a) is introduced without filtering the atmospheric gas particles; (c) introducing: maintaining a gas pressure above 100 mTorr in the gas path; using an ion source connected to the gas path The method includes the steps of: generating ions from the gas particles to be analyzed; and detecting the ions according to a mass to charge ratio of the ions using a detector connected to the gas path.

  Embodiments of the method can include one or more of the following features.

  The atmospheric gas particles may include at least one of nitrogen molecules and oxygen molecules.

  The method may include maintaining a gas pressure of greater than 500 mTorr (e.g., 1 Torr) in the gas path. The method can include continuously introducing the mixture of gas particles into the gas path for at least 10 seconds (at least 30 seconds, at least 2 minutes). The method adjusts the ion source such that ions are generated from the gas particle to be analyzed for a continuous period of 10 seconds or more (e.g., for a continuous period of 30 seconds or more, for a continuous period of 2 minutes or more) Can be included.

  Embodiments of the method can include any of the other features disclosed herein, as appropriate, in any combination.

  In another aspect, the present disclosure provides a single mechanical pump configured to control gas pressure in an ion source, an ion trap, an ion detector, the ion source, the ion trap, and the ion detector. And a controller connected to the ion source, the ion trap, and the ion detector, wherein the single mechanical pump controls the gas pressure. Operating at a rate of less than 6000 cycles per minute, and during operation of the mass spectrometer, the controller operates the ion detector to detect ions generated by the ion source according to the mass to charge ratio of the ions. It is configured to

  Embodiments of the mass spectrometer may include one or more of the following features.

  The single mechanical pump can include a scroll pump. The single mechanical pump can operate at less than 4000 cycles per minute to control the gas pressure.

  During operation of the mass spectrometer, the single mechanical pump can maintain a gas pressure between 100 mTorr and 100 Torr in at least two of the ion source, the ion trap, and the ion detector. During operation of the mass spectrometer, the single mechanical pump can maintain a gas pressure between 500 mTorr and 10 Torr in at least two of the ion source, the ion trap, and the ion detector. During operation of the mass spectrometer, the single mechanical pump can maintain a common gas pressure in at least two of the ion source, the ion trap, and the ion detector. During operation of the mass spectrometer, the single mechanical pump can maintain a gas pressure with a difference of 10 Torr or less at the ion source, the ion trap, and the ion detector.

  The controller can be connected to the pump, and the controller can be configured to control the number of pumps during operation of the mass spectrometer. In operation of the mass spectrometer, the controller may be configured to detect ions generated by the ion source using the ion detector and adjust the number of pumps based on the detected ions.

  The ion source can include a glow discharge ionization source, a dielectric barrier discharge ionization source, and / or a capacitor discharge ionization source.

  The mass spectrometer is configured to surround the ion source and the ion trap and include a housing comprising the ion source and a first plurality of electrodes connected to the ion trap; and to engage the first plurality of electrodes And a support base with a second plurality of electrodes, the housing being a pluggable module configured to releasably connect to the support base. The housing can surround the pump. The controller is attachable to the support base. The support base can include a printed circuit board. The electrical processor can be electrically connected to the ion source and the ion trap via the support base.

  The largest dimension of the mass spectrometer may be less than 35 cm. The total mass of the mass spectrometer is less than 4.5 kg.

  The mass spectrometer embodiments can include any of the other features disclosed herein, as appropriate, in any combination.

  In a further aspect, the present disclosure includes using a single mechanical pump to control gas pressure in an ion source of a mass spectrometer, an ion trap, and an ion detector, and ions generated by the ion source. Using the ion detector to detect according to the mass to charge ratio of the ions, and using the single mechanical pump to control the gas pressure controls the gas pressure Operating the pump at a frequency less than 6000 cycles per minute.

  Embodiments of the method can include one or more of the following features.

  The method may include operating the pump at a frequency less than 4000 cycles per minute to control the gas pressure. The method comprises maintaining a gas pressure between 100 mTorr and 100 Torr (e.g., between 500 mTorr and 10 Torr) in at least two of the ion source, the ion trap, and the ion detector. Can be included.

  The method can include maintaining a common gas pressure in at least two of the ion source, the ion trap, and the ion detector. The method can include maintaining a gas pressure at the ion source, the ion trap, and the ion detector with a difference of less than 10 Torr.

  The method may include adjusting the number of times of the pump based on the detected ions (e.g., based on the abundance of the detected ions).

  Embodiments of the method can include any of the other features disclosed herein, as appropriate, in any combination.

  In another aspect, the present disclosure is a mass spectrometer, which includes an ion source, an ion trap, an ion detector, a user interface, the ion source, the ion trap, the ion detector, and the user interface. And a controller connected to the mass spectrometer, the controller operating the mass spectrometer to detect and detect ions generated by the ion source using the ion detector. Identifying the chemical name associated with the selected ion and displaying the chemical name on the user interface, the user interface being activated by the user after the chemical name is displayed, the controller Control means for displaying the spectrum of the detected ion on the user interface No.

  Embodiments of the mass spectrometer may include one or more of the following features.

  Displaying the spectrum of the detected ion includes displaying the abundance of the detected ion as a function of the mass to charge ratio of the ion. The control means may include at least one of a button, a switch, and an area of a touch screen display. In operation of the mass spectrometer, the controller can be further configured to display the hazard associated with the detected ion on the user interface.

  The ion source may be at least one of a glow discharge ionization source, a capacitor discharge ionization source, and a dielectric barrier discharge ionization source.

  In operation of the mass spectrometer, the controller may be configured such that the spectrum of the detected ions is not displayed unless the control means is operated.

  The ion detector can include a Faraday detector.

  The mass spectrometer may include a pressure regulation system, and when operating the mass spectrometer, the pressure regulation system may be between 100 mTorr and 100 Torr at the ion trap and the ion detector (e.g. 500 It is configured to maintain the gas pressure between millitorr and 10 torr.

  The pressure control system may include a scroll pump.

  The mass spectrometer includes a pluggable module including the ion source, the ion trap, and the ion source and a first plurality of electrodes connected to the ion trap, a voltage source, and the first plurality of electrodes. The support base may include a second plurality of electrodes configured to engage, the pluggable module being configured to releasably connect to the support base.

  The pluggable module can include the ion detector. The pluggable module can include a pressure control system.

  The mass spectrometer is a housing surrounding the pluggable module and the support base, the mass spectrometer having an opening disposed adjacent to the pluggable module and inserting the pluggable module into the opening A housing can be included that is configured to be releasably connectable to the support base.

  The largest dimension of the mass spectrometer may be less than 35 cm. The total mass of the mass spectrometer can be less than 4.5 kg.

  The mass spectrometer embodiments can include any of the other features disclosed herein, as appropriate, in any combination.

  In a further aspect, the present disclosure is a mass spectrometer comprising an ion source, an ion trap, an ion detector, a user interface, the ion source, the ion trap, the ion detector, and the user interface. A mass spectrometer including a connected controller, the user interface including control means by which a user of the mass spectrometer can operate in either of at least two states, the controller operating in the operation of the mass spectrometer Using the ion detector to detect ions generated by the ion source, identifying a chemical name associated with the detected ions, and the control means being activated to a first state, The chemical name is displayed on a user interface, and when the control means is actuated to a second state, the user It is configured to display the spectrum of the detected ions on the face.

  Embodiments of the mass spectrometer may include one or more of the following features.

  The controller may be further configured to display the chemical name on the user interface when the controller is actuated to the second state. Displaying the spectrum of the detected ion may include displaying the abundance of the detected ion as a function of the mass to charge ratio of the ion. The control means may include at least one of a button, a switch, and an area of a touch screen display.

  The ion source may be at least one of a glow discharge ionization source, a capacitor discharge ionization source, and / or a dielectric barrier discharge ionization source.

  The mass spectrometer may include a pressure regulation system connected to the controller, and in operation of the mass spectrometer, the pressure regulation system comprises 100 milliTorr and 100 Torr at the ion trap and the ion detector. To maintain the gas pressure (e.g., between 500 mTorr and 10 Torr). The pressure control system may include a scroll pump.

  The mass spectrometer includes a pluggable module including the ion source, the ion trap, and the ion source and a first plurality of electrodes connected to the ion trap, a voltage source, and the first plurality of electrodes. And a support base including a second plurality of electrodes configured to mate, the pluggable module being configured to releasably connect to the support base. The pluggable module may include the ion detector and / or a pressure control system.

  The mass spectrometer is a housing surrounding the pluggable module and the support base, the mass spectrometer having an opening disposed adjacent to the pluggable module and inserting the pluggable module into the opening A housing can be included that is configured to be releasably connectable to the support base.

  The largest dimension of the mass spectrometer may be less than 35 cm. The total mass of the mass spectrometer can be less than 4.5 kg.

  The mass spectrometer embodiments can include any of the other features disclosed herein, as appropriate, in any combination.

  In another aspect, the present disclosure provides a mass spectrometer comprising: an ion source, an ion trap, an ion detector, a sample inlet, and a pressure control system, said ion source The ion trap, the ion detector, the sample inlet, and the pressure control system are connected to a gas path, and when the mass spectrometer is in operation, gas particles may flow through the gas path only through the sample inlet. Introduced therein, the pressure regulation system being configured to maintain a gas pressure between 100 mTorr and 100 Torr in the gas path, and the ion detector being generated from the gas particles by the ion source The ions are configured to be detected according to the mass to charge ratio of the ions.

  Embodiments of the mass spectrometer may include one or more of the following features.

  The pressure regulation system may be configured to maintain the gas pressure between 500 mTorr and 10 Torr. The pressure regulation system may be configured to maintain the gas pressure above 500 mTorr.

  The ion source can include at least one of a glow discharge ionization source, a capacitor discharge ionization source, and a dielectric barrier discharge ionization source.

  The largest dimension of the mass spectrometer may be less than 35 cm. The total mass of the mass spectrometer can be less than 4.5 kg.

  The pressure control system may include a scroll pump.

  The sample inlet may be configured such that gas particles introduced into the gas path include gas particles to be analyzed and atmospheric gas particles.

  The mass spectrometer may include a valve connected to the sample inlet and a controller connected to the valve, and when operating the mass spectrometer, the controller may control the gas particles as the sample. It can be configured to introduce continuously into the gas path via the inlet for at least 30 seconds (at least 1 minute, for at least 2 minutes).

  The mass spectrometer may include a controller connected to the ion source, and during operation of the mass spectrometer, the controller adjusts a potential applied to the ion source such that ions are from the ion source Can be generated continuously from the gas particles for at least 30 seconds (at least 1 minute, for at least 2 minutes).

  The mass spectrometer includes a pluggable module including the ion source, the ion trap, and the ion source and a first plurality of electrodes connected to the ion trap, a voltage source, and the first plurality of electrodes. The support base may include a second plurality of electrodes configured to engage, the pluggable module being configured to releasably connect to the support base. The pluggable module can include the pressure regulation system.

  The mass spectrometer is a housing surrounding the pluggable module and the support base, the mass spectrometer having an opening disposed adjacent to the pluggable module and inserting the pluggable module into the opening A housing can be included that is configured to be releasably connectable to the support base.

  The pressure regulation system may include a single mechanical pump, and the single mechanical pump may operate at less than 6000 cycles per minute to maintain the gas pressure in the gas path during operation of the mass spectrometer. It is configured to work with a number of times.

  The mass spectrometer embodiments can include any of the other features disclosed herein, as appropriate, in any combination.

  In a further aspect, the present disclosure is the step of introducing a mixture of gas particles into a gas path of a mass spectrometer via a single gas inlet, wherein the mixture of gas particles is to be analyzed gas particles and air. Introducing only containing gas particles, maintaining a gas pressure between 100 mTorr and 100 Torr in the gas path, and generating ions of the ions generated from the analyzed gas particles in a mass to charge ratio of the ions And detecting according to.

  Embodiments of the method can include one or more of the following features.

  The method can include maintaining the gas pressure between 500 mTorr and 10 Torr. The method can include maintaining the gas pressure above 500 mTorr.

  The method comprises continuously introducing the mixture of gas particles into the gas path for at least 30 seconds (at least 1 minute, at least 2 minutes) via the single gas inlet. Can.

  The method adjusts the potential applied to the ion source of the mass spectrometer to continuously generate ions from the gas particles to be analyzed for at least 30 seconds (at least 1 minute, for at least 2 minutes) Can be included.

  The method may include operating the single mechanical pump at a frequency less than 6000 cycles per minute to maintain the gas pressure in the gas path.

  Embodiments of the method can include any of the other features disclosed herein, as appropriate, in any combination.

  In another aspect, the present disclosure is an ion source featuring an outlet electrode, the ion source passing ions through the outlet electrode as it exits the ion source, and an inlet disposed adjacent to the outlet electrode. A mass spectrometer comprising an ion trap featuring an electrode, an ion detector, and a pressure control system, the outlet electrode comprising one or more apertures defining a cross-sectional shape of the outlet electrode, The inlet electrode comprises one or more apertures defining the cross-sectional shape of the inlet electrode; the cross-sectional shape of the outlet electrode substantially corresponds to the cross-sectional shape of the inlet electrode; the mass spectrometer During operation, the pressure regulation system is configured to maintain a gas pressure of at least 100 mTorr in the ion trap, the ion detector being generated by the ion source. And the ions are arranged to detect in accordance with mass-to-charge ratio of the ions.

  Embodiments of the mass spectrometer may include one or more of the following features.

  The ion trap comprises one or more ion chambers, which define the cross-sectional shape of the ion trap, the cross-sectional shape of the ion trap being the cross-sectional shape of the inlet electrode It can match substantially.

  The one or more apertures of the exit electrode may comprise a number of apertures arranged in a rectangular or square array. The one or more apertures of the outlet electrode may include a number of apertures arranged in a hexagonal array. The one or more apertures of the outlet electrode may comprise an aperture with a rectangular cross-sectional shape. The one or more apertures of the outlet electrode may comprise an aperture with a helically shaped cross-sectional shape. The one or more apertures of the outlet electrode may comprise an aperture with a serpentine cross-sectional shape. The one or more apertures of the exit electrode may include four apertures (eg, eight or more apertures, 24 or more apertures, 100 or more apertures). The one or more apertures of the outlet electrode may include a plurality of apertures arranged in a serpentine pattern.

  The mass spectrometer may include a voltage source connected to the outlet electrode and a first electrode of the ion source, and a controller connected to the voltage source, the controller operating the mass spectrometer. Can be configured to operate the ion source in one of at least two modes by applying different potentials to the first electrode and the outlet electrode with reference to a common ground potential. In the first mode of the at least two modes, the controller is configured to apply a potential to the first electrode and the outlet electrode such that the first electrode has a positive potential with respect to the common ground potential. And in the second mode of the at least two modes, the controller is configured to apply a potential to the first and second electrodes such that the first electrode has a negative potential with respect to the common ground. it can.

  The mass spectrometer is a user interface with selectable control means, the controller changing the operating mode of the ion source when the control means is activated during operation of the mass spectrometer May be configured to include a user interface.

  The ion source can include a glow discharge ionization source.

  The mass spectrometer may include a detector connected to the controller, and in operation of the mass spectrometer, the controller detects ions generated by the ion source using the ion detector. The potential applied to the first electrode and the outlet electrode may be adjusted based on the detected ions to control a period during which the ion source continuously generates ions. During operation of the mass spectrometer, the ion source can generate ions in a plurality of ionization cycles that define the ion source frequency, each ionization cycle comprising a first interval at which the ions are generated, and a second at which the ions are not generated. And the first and second intervals define a duty cycle, and the controller sets the duty cycle to a value between 1% and 40% (e.g., between 1% and 20%). , Values between 1% and 10%).

  During operation of the mass spectrometer, the controller determines when the ion source is to be cleaned based on the detected ions, and the duty cycle of the ion source is 50% and 90%. The ion source may be configured to operate for at least 30 seconds to clean the ion source.

  The pressure regulation system may be configured to maintain a gas pressure of between 100 mTorr and 100 Torr (e.g., between 500 mTorr and 10 Torr) in the ion trap.

  The largest dimension of the mass spectrometer may be less than 35 cm. The total mass of the mass spectrometer can be less than 4.5 kg.

  The mass spectrometer embodiments can include any of the other features disclosed herein, as appropriate, in any combination.

  In a further aspect, the present disclosure provides an ion source, an ion trap, an ion detector, a pressure regulation system, a voltage source connected to the ion source, the ion trap, the ion detector, and the pressure regulation system. A mass spectrometer including the ion source, the ion trap, the ion detector, and a controller connected to the voltage source, wherein the controller operates the ion source in operation of the mass spectrometer. Operating to generate ions from gas particles, operating the ion detector to detect ions generated by the ion source, and adjusting the resolution of the mass spectrometer based on the detected ions Configured

  Embodiments of the mass spectrometer may include one or more of the following features.

  The controller may be connected to the pressure regulation system and may be configured to regulate the degree of decomposition by operating the pressure regulation system to change the gas pressure in at least one of the ion source and the ion trap. The controller may be configured to adjust the degree of decomposition by operating the pressure regulation system to reduce the gas pressure in the at least one of the ion source and the ion trap.

  The controller may be configured to repeatedly apply a potential to the central electrode of the ion trap using the voltage source to eject ions from the ion trap, and the repetitive application of the potential defines a number of repetitions of the potential. The controller may be further configured to adjust the resolution by changing the number of repetitions of the potential. The controller may be configured to increase the resolution by increasing the repetitive application of the potential.

  The controller may be configured to adjust the resolution by changing the maximum amplitude of the potential applied by the voltage source to the central electrode of the ion trap.

  The controller may be configured to apply an axial potential difference between the electrodes at opposite ends of the ion trap using the voltage source to adjust the resolution by changing the magnitude of the axial potential difference. The controller may be configured to increase the resolution by increasing the magnitude of the axial potential difference.

  The controller may be configured to repeatedly apply a potential difference between the electrodes of the ion source using the voltage source to generate the ions, wherein the repeated application of the potential defines a repeat number of the ion source, The controller may be further configured to adjust the resolution by changing the number of repetitions of the ion source. The controller may be configured to synchronize the number of repetitions of the ion source with the number of repetitions of the potential applied to the central electrode of the ion trap.

  The controller may be configured to repeatedly apply a potential difference between the electrodes of the ion source using the voltage source, wherein the repetitive application of the potential defines a repetition period of the ion source, the repetition period comprising the potential difference A first time interval applied between the electrodes of the ion source, and a second time interval where the potential difference is not applied between the electrodes of the ion source; the controller is further configured to: The resolution may be adjusted by adjusting a duty cycle of the duty cycle, the duty cycle corresponding to a ratio of the first time interval to the repetition period. The controller may be configured to increase the resolution by decreasing the duty cycle of the ion source.

  The mass spectrometer is a gas path, and is a gas path to which the ion source, the ion trap, the ion detector, and the pressure control system are connected, and a gas inlet port connected to the gas path. And a gas inlet provided with a valve connected to the controller, and in order to adjust the degree of decomposition, the controller controls the valve to cause buffer gas particles to flow through the buffer gas inlet. Are configured to adjust the rate of introduction into the gas path via The controller may be configured to increase the rate at which buffer gas particles are introduced into the gas path in order to increase the degree of decomposition.

  During operation of the mass spectrometer, the controller repeatedly operates: the ion source to generate ions from gas particles, and the ion detector to detect ions generated by the ion source, the mass The resolution of the analyzer is adjusted based on the detected ions and these are performed until the resolution of the mass spectrometer reaches a threshold; the resolution of the mass spectrometer is at least equal to the threshold Activating the ion detector to detect ions generated from the gas particle when it is sized; ions detected when the resolution of the mass spectrometer is at least as large as the threshold value Identifying information relating to the identity of the gas particles based on; and displaying the information on a user interface. The information may include the chemical name of the gas particle and / or information on the hazard associated with the gas particle and / or information on the type of substance to which the gas particle corresponds.

  During operation of the mass spectrometer, the controller may be configured to adjust the potential source such that an electrical potential is applied to the central electrode of the ion trap only when the resolution reaches the threshold.

  During operation of the mass spectrometer, the pressure regulation system is between 100 mTorr and 100 Torr (e.g., 500 mTorr and 10 Torr) in at least two of the ion source, the ion trap, and the ion detector. Can be configured to maintain the gas pressure).

  The mass spectrometer comprises a pluggable module comprising: the ion source, the ion trap, the detector, and the ion source, the ion trap, and a first plurality of electrodes connected to the detector. And a support base comprising a second plurality of electrodes configured to releasably engage the first plurality of electrodes, wherein the voltage source and the controller are attached to the support base and the pluggable The module is configured to releasably connect to the support base.

  The largest dimension of the mass spectrometer may be less than 35 cm. The total mass of the mass spectrometer can be less than 4.5 kg.

  The mass spectrometer embodiments can include any of the other features disclosed herein, as appropriate, in any combination.

  In another aspect, the present disclosure relates to introducing gas particles into an ion source of a mass spectrometer, generating ions from the gas particles, and detecting the ions using a detector of the mass spectrometer. Providing a step of adjusting the resolution of the mass spectrometer based on the detected ions.

  Embodiments of the method can include one or more of the following features.

  The adjusting the degree of decomposition may include changing a gas pressure in at least one of the ion source and the ion trap. The method may include the step of increasing the degree of decomposition by reducing the gas pressure in the at least one of the ion source and the ion trap.

  The method comprises repeatedly applying a potential to a central electrode of the trap to eject ions from the ion trap, wherein the repetitive application of the potential defines a number of repetitions of the potential. The controller may further include adjusting the resolution by changing the number of repetitions of the potential. The method may include increasing the resolution by increasing the number of repetitions of the potential. The method may include adjusting the resolution by changing the maximum amplitude of the potential applied to the central electrode of the ion trap.

  The method can include applying an axial potential difference between the electrodes at opposite ends of the ion trap, and adjusting the resolution by changing the magnitude of the axial potential difference. The method may include increasing the resolution by increasing the magnitude of the axial potential difference.

  The method comprises repeatedly applying a potential difference between the electrodes of the ion source to generate the ions, wherein the repetitive application of the potential defines applying a repetition number of the ion source; Adjusting the resolution by changing the number of repetitions of the source. The controller may be configured to synchronize the number of repetitions of the ion source with the number of repetitions of the potential applied to the central electrode of the ion trap.

  The method comprises: repeatedly applying a potential difference between the electrodes of the ion source, wherein the repeated application of the potential defines a repetition period of the ion source, and in the repetition period, the potential difference is the ion source. Adjusting the duty cycle of the ion source, including applying a first time interval applied between the electrodes and a second time interval in which the potential difference is not applied between the electrodes of the ion source; Adjusting the resolution thereby, wherein the duty cycle corresponds to the ratio of the first time interval to the repetition period. The method may include reducing the resolution by reducing the duty cycle of the ion source.

  In order to adjust the degree of decomposition, the method may include increasing the rate at which buffer gas particles are introduced into the gas path of the mass spectrometer. In order to increase the degree of decomposition, the method may include increasing the rate at which buffer gas particles are introduced into the gas path.

  The method comprises: repeatedly operating the ion source to generate ions from gas particles; operating the ion detector to detect ions generated by the ion source; and the mass spectrometer Adjusting the resolution based on the detected ions, which are performed until the resolution of the mass spectrometer reaches a threshold; the resolution of the mass spectrometer is at least equal to the threshold Activating the ion detector to detect ions generated from the gas particle when it is sized; and detected when the resolution of the mass spectrometer is at least as large as the threshold value. Identifying information related to the identity of said gas particles based on selected ions; and displaying said information on a user interface. Can. The information may include the chemical name of the gas particle and / or information on the hazard associated with the gas particle and / or information on the type of substance to which the gas particle corresponds.

  The method may include applying a potential to the central electrode of the ion trap only when the resolution reaches the threshold.

  The method comprises maintaining a gas pressure between 100 mTorr and 100 Torr (e.g., between 500 mTorr and 10 Torr) in at least two of the ion source, the ion trap, and the ion detector. Can be included.

  Embodiments of the method can include any of the other features disclosed herein, as appropriate, in any combination.

  In a further aspect, the present disclosure provides a gas pressure control system featuring an ion source, an ion trap, an ion detector, and a single mechanical pump, the ion source, the ion trap, and the ion detector. Providing a mass spectrometer including a connected controller, wherein, in operation of the mass spectrometer, the gas pressure adjustment subsystem comprises 100 millitorr in at least two of the ion source, the ion trap, and the ion detector. Configured to maintain a gas pressure between 100 and 100 Torr, and the controller is configured to operate the ion detector to detect the ions generated by the ion source according to the mass to charge ratio of the ions. The single mechanical pump operates at a frequency of less than 6000 cycles per minute to maintain the gas pressure.

  Embodiments of the mass spectrometer may include one or more of the following features. In operation, the gas pressure regulation system can be configured to maintain a gas pressure between 100 mTorr and 100 Torr in the ion trap and the ion detector. In operation, the gas pressure regulation system may be configured to maintain a gas pressure between 100 mTorr and 100 Torr in the ion source and the ion trap. In operation, the gas pressure regulation system can be configured to maintain a gas pressure between 100 mTorr and 100 Torr in the ion source, the ion trap, and the ion detector.

  The mechanical pump may be a scroll pump.

  In operation, the gas pressure regulation system may be configured to maintain a gas pressure with a difference of less than 10 Torr in at least two of the ion source, the ion trap, and the ion detector. In operation, the gas pressure regulation system may be configured to maintain a gas pressure at the ion source, the ion trap, and the ion detector with a difference less than 10 Torr. In operation, the gas pressure regulation system can be configured to maintain the same gas pressure in at least two of the ion source, the ion trap, and the ion detector.

  The mass spectrometer is a gas path, and includes a gas path to which the ion source, the ion trap, the ion detector, and the gas pressure control system are connected, and a gas inlet port connected to the gas path. And, during operation of the mass spectrometer, gas particles to be analyzed are introduced into the gas path through the gas inlet, and the total pressure in the gas path is between 100 mTorr and 100 Torr. And a gas inlet configured as described above. The gas inlet may be configured such that during operation of the mass spectrometer, a mixture of gas particles comprising the analyzed gas particles and atmospheric gas particles is drawn into the gas inlet, the mixture of gas particles being It is not filtered to remove atmospheric gas particles before being introduced into the gas path.

  The mass spectrometer is a gas path, and a gas path to which the ion source, the ion trap, the ion detector, and the gas pressure adjustment system are connected, and a sample gas inlet port connected to the gas path And a buffer gas inlet connected to the gas path, during operation of the mass spectrometer: gas particles to be analyzed are introduced into the gas path via the sample gas inlet; Buffer gas particles are introduced into the gas path via the buffer gas inlet and a combined pressure of the analyzed gas particles in the gas path and the buffer gas particles is between 100 mTorr and 100 Torr. The sample gas inlet and the buffer gas inlet are configured to be as follows. The buffer gas particles may include at least one of nitrogen molecules and noble gas molecules.

  The mass spectrometer is releasably connectable to the ion source, the ion trap, and the pluggable module including the ion source and the first plurality of electrodes connected to the ion trap, and the first plurality of electrodes. The support base may further include a second plurality of electrodes configured to engage, the pluggable module being connectable to the support base and separable from the support base. The mass spectrometer may include an attachment mechanism configured to secure the pluggable module to the support base when the first plurality of electrodes engage the second plurality of electrodes. The first plurality of electrodes can include a pin, and the second plurality of electrodes can include a socket configured to receive the pin.

  The pluggable module can include the ion detector, and the first plurality of electrodes can be connected to the ion detector. The pluggable module can include the mechanical pump.

  The mass spectrometer may include a voltage source, the voltage source and the controller being attached to the support base and connected to the second plurality of electrodes.

  The support base can include a printed circuit board. The controller may be further connected to the ion source and the ion trap when the pluggable module is connected to the support base.

  The single mechanical pump can operate at less than 4000 cycles per minute to maintain the gas pressure.

  The largest dimension of the mass spectrometer may be less than 35 cm. The total mass of the mass spectrometer can be less than 4.5 kg.

  The mass spectrometer embodiments can include any of the other features disclosed herein, as appropriate, in any combination.

  In another aspect, the present disclosure uses a single mechanical pump operating at less than 6000 cycles per minute to generate gas pressures in at least two of the mass spectrometer ion source, ion trap, and ion detector. Providing a method comprising the steps of maintaining and detecting the ions generated by said ion source according to the mass to charge ratio of said ions, said ion source, said ion trap, and said at least two of said ion detectors. In one, the gas pressure is maintained between 100 mTorr and 100 Torr.

  Embodiments of the method can include one or more of the following features.

  The gas pressure in the ion source and the ion trap can be maintained between 100 mTorr and 100 Torr. The gas pressure in the ion trap and the detector can be maintained between 100 mTorr and 100 Torr. The method can include maintaining a gas pressure at a difference of less than 10 Torr in at least two of the ion source, the ion trap, and the ion detector. The method may further include maintaining the same gas pressure in the ion source, the ion trap, and the ion detector.

  The method can include introducing a mixture of gas particles into a gas path connecting the ion source, the ion trap, and the ion detector, and the mixture of gas particles is analyzed A mixture of gas particles, comprising gas particles and atmospheric gas particles, is not filtered to remove atmospheric gas particles before being introduced into the gas path.

  The method may include operating the mechanical pump at a frequency less than 4000 cycles per minute to control the gas pressure.

  Embodiments of the method can include any of the other features disclosed herein, as appropriate, in any combination.

  Unless defined otherwise, technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the subject matter herein, suitable methods and materials are described below. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety. In case of conflict, the present specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting.

  The details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features and advantages will be apparent from the detailed description, the drawings, and the claims.

FIG. 1A is a schematic of a compact mass spectrometer. FIG. 1B is a cross-sectional view of one embodiment of a mass spectrometer. FIG. 1C is a cross-sectional view of another embodiment of a mass spectrometer. FIG. 1D is a schematic view of a mass spectrometer with the components attached to a support base. FIG. 1E is a schematic view of a mass spectrometer with a pluggable module. FIG. 1F is a schematic view of an attachment mechanism for connecting a mass spectrometer module to a support base. FIG. 2A is a schematic view of a glow discharge ion source. FIG. 2B is a schematic view of a glow discharge ion source. FIG. 2C is a schematic view showing an electrode of an ion source provided with an aperture. FIG. 2D is a schematic view showing an electrode of an ion source provided with an aperture. FIG. 2E is a schematic view showing an electrode of an ion source provided with an aperture. FIG. 2F is a schematic view showing an electrode of an ion source provided with an aperture. FIG. 2G is a schematic view showing an electrode of an ion source provided with an aperture. FIG. 2H is a schematic view showing an electrode of an ion source provided with an aperture. FIG. 2I is a graph showing the bias charge applied to the electrodes of the ion source. FIG. 2J is a graph showing the bias charge applied to the electrodes of the ion source to clean the ion source. FIG. 2K is a schematic view of a capacitor discharge ion source. FIG. 3A is a cross-sectional view of one embodiment of an ion trap. FIG. 3B is a schematic view of another embodiment of an ion trap. FIG. 3C is a cross-sectional view of the ion trap of FIG. 3B. FIG. 4A is a schematic diagram of a voltage source. FIG. 4B is a graph showing the unamplified modulation signal of the ion trap. FIG. 4C is a graph showing the corrected signal of the ion trap. FIG. 4D is a graph showing a reference carrier waveform. FIG. 4E is a graph showing the amplified modulation signal of the ion trap. FIG. 4F is a diagram illustrating a resonant circuit for amplifying the signal of FIG. 4E. FIG. 5A is a perspective view of one embodiment of a Faraday cup charged particle detector. FIG. 5B is a schematic view of the Faraday cup detector of FIG. 5A. FIG. 5C is a schematic view of another embodiment of a Faraday cup detector. FIG. 5D is a schematic view of a Faraday cup detector array. FIG. 6A is a schematic of a pressure regulation subsystem with a scroll pump. FIG. 6B is a schematic view of a scroll pump flange. FIG. 7A is a perspective view of a compact mass spectrometer. FIG. 7B is a cross section of an embodiment of a compact mass spectrometer. FIG. 7C is a cross-sectional view of a compact mass spectrometer embodiment. FIG. 8A is a flow chart showing a series of steps for measuring mass spectral information and displaying information about a sample. FIG. 8B is a schematic view of one embodiment of a compact mass spectrometer. FIG. 8C is a flow chart showing a series of steps for measuring mass spectral information and adjusting a mass spectrometer configuration.

  Like reference symbols in the various drawings indicate like elements.

I. Overview Mass spectrometers used for chemical identification are large, complex instruments that typically consume considerable power. Such instruments are heavy and too bulky to carry, so they are limited to use in a substantially fixed environment. In addition, conventional mass spectrometers are typically expensive and highly trained to interpret the spectra of the ion information patterns produced by these instruments to deduce the identity of the chemical being analyzed Requires an operator.

  To achieve high sensitivity and resolution, conventional mass spectrometers typically use a variety of components designed for low gas pressure operation. For example, conventional ion detectors, such as electron multipliers, do not operate effectively at pressures above approximately 10 mTorr. As another example, thermionic emitters used in conventional ion sources are only suitable for operation at pressures less than approximately 10 mTorr, and generally can not be used even if the oxygen concentration is not very high. In addition, conventional mass spectrometers have mass analyzers with a geometry specifically designed for operation only at pressures typically less than 10 mTorr, specifically at pressures in the microTorr range As a result, not only are conventional mass spectrometers configured for operation at low pressure, but conventional mass spectrometers can not operate at higher gas pressures due to the components they use. Higher gas pressures can, for example, destroy some components of a conventional mass spectrometer. Although not so dramatic, some components are simply inoperable or simply inefficient at higher gas pressures, and these mass spectrometers can provide useful mass spectral information. It disappears. As a result, operating at higher pressures (e.g., pressures above 100 mTorr) requires mass spectrometers with very different configurations and components.

  To achieve low pressure, conventional mass spectrometers typically include a series of pumps that evacuate the internal volume of the spectrometer. For example, a conventional mass spectrometer can include a roughing pump that sharply reduces the internal pressure of the system and a turbo molecular pump that further reduces the internal pressure to the microtorr value. Turbo molecular pumps are large and consume considerable power. However, these considerations are only of secondary importance in conventional mass spectrometers, and the most important consideration is to achieve high resolution in the measured mass spectrum. Using the above-described components operating at low pressure, conventional mass spectrometers can usually achieve a resolution of 0.1 atomic mass unit (amu) or better.

  In contrast to heavy and bulky conventional mass spectrometers, the compact mass spectrometers disclosed herein are designed for low power and high efficiency operation. In order to achieve low power operation, the compact mass spectrometers disclosed herein do not include turbo molecular pumps or other high power consumption vacuum pumps. Instead, this compact mass spectrometer typically includes only a single mechanical pump that operates at a low frequency, which significantly reduces power consumption.

  By using smaller pumps, the compact mass spectrometers disclosed herein typically operate in the pressure range of 100 mTorr to 100 Torr, which is above the operating pressure range of conventional mass spectrometers. It is quite expensive. Conventional mass spectrometers can not be adapted to operate at these higher pressures, because the components used in conventional mass spectrometers (eg electron multipliers, thermionic emitters) And ion traps do not work in the pressure range at which the compact mass spectrometer disclosed herein operates. In addition, conventional mass spectrometers are generally not adapted to operate at higher internal pressure, because doing so would reduce the resolution of the mass spectrum measured using the device. When using such a device, there is no reason to modify the device to reduce the resolution, as it is a general goal to obtain a mass spectrum with the highest resolution possible.

  However, the compact mass spectrometers disclosed herein provide the user with different types of information than conventional mass spectrometers. In particular, the compact mass spectrometers disclosed herein typically report information such as the name of the chemical being analyzed, hazard information associated with the substance, and / or the type to which the substance belongs. Do. The compact mass spectrometers disclosed herein can also, for example, report if the substance is a specific target substance. Typically, the recorded mass spectrum is not displayed to the user unless the user activates the control means to display this spectrum. Consequently, unlike conventional mass spectrometers, the compact mass spectrometers disclosed herein do not need to acquire mass spectra with maximum resolution. Instead, further increase in resolution is not a significant performance requirement if the resulting spectrum is sufficiently high quality to determine the information to be reported to the user.

  By operating at lower resolutions (typically, mass spectra are obtained with resolutions between 1 amu and 10 amu), the compact mass spectrometers disclosed herein have the conventional mass Power consumption is considerably reduced compared to the analyzer. For example, the compact mass spectrometer disclosed herein comprises a small ion trap that operates efficiently at pressures of 100 mTorr to 100 Torr to separate ions of different mass-to-charge ratios, at the same time The small size significantly reduces power consumption over conventional mass analyzers such as ion traps. For example, as the size of the cylindrical ion trap decreases, the maximum voltage applied to this trap to separate ions decreases and the frequency at which the voltage is applied increases. As a result, the size of the inductors and / or resonators used in the power supply circuit is reduced and the size and power consumption requirements of other components used to generate the maximum voltage are also reduced.

  Furthermore, the compact mass spectrometers disclosed herein further reduce power consumption as compared to ion sources such as thermionic emitters typically provided in conventional mass spectrometers and / or glow discharge ionization sources and / or An efficient ion source such as a capacitor discharge ionization source is provided. The compact mass spectrometers disclosed herein use an efficient, low-power detector such as a Faraday detector, rather than the more power-consuming electron multipliers provided in conventional mass spectrometers. ing. Because of these low power components, the compact mass spectrometers disclosed herein operate efficiently and have relatively low power consumption. They are powered from a standard battery-based power source (eg, a lithium ion battery) and are portable with a hand-held form factor.

  Conventional mass spectrometers provide high resolution mass spectra directly to the user, and are generally unsuitable for applications involving hand-held scanning of material by specially trained personnel. In particular, for applications such as in-situ security scanning at traffic hubs such as airports and train stations, conventional mass spectrometers are not a viable solution. In contrast, such applications benefit from a mass spectrometer that is compact as described above, requires relatively little power to operate, and provides information that can be easily interpreted by highly trained personnel. . Compact, low cost mass spectrometers are also useful for a variety of other applications. For example, such devices can be used in the laboratory to rapidly describe the properties of unknown compounds. Because these are low cost and have a small footprint, the laboratory can be provided with a personal analyzer for the operator, reducing or eliminating the need to reserve analysis time in a centralized mass spectrometry facility. The compact mass spectrometer can also be used as a medical diagnostic test in both the clinical environment and the residence of individual patients. Technicians who perform such tests can easily interpret the information provided by such analyzers to provide real-time evaluation information to patients, and provide rapidly updated information to healthcare facilities, physicians and other healthcare professionals. Can be given to

  The present disclosure is a small-sized, low-power mass spectrometer that includes various information including identification information of chemical substances scanned by the analyzer and / or a class to which the substance belongs (eg, acid, base, strong oxidizing substance) A mass spectrometer is provided that provides the user with relevant contextual information including information on explosives, nitrated compounds, hazard information associated with the substance, and safety instructions and / or information. These analyzers operate at higher internal gas pressures than conventional mass spectrometers. By operating at higher pressures, the size and power consumption of these compact mass spectrometers is significantly reduced compared to conventional mass spectrometers. Furthermore, although these analyzers operate at higher pressures, their degree of degradation is sufficient to provide accurate identification and quantification of a wide variety of chemicals.

  FIG. 1A is a schematic diagram of one embodiment of a compact mass spectrometer 100. The analyzer 100 includes an ion source 102, an ion trap 104, a voltage source 106, a controller 108, a detector 118, a pressure regulation subsystem 120, and a sample inlet 124. The sample inlet 129 includes a valve 129. Analyzer 100 optionally includes a buffer gas source 150. The components of the analyzer 100 are contained within a housing 122. The controller 108 includes an electronic processor 110, a user interface 112, a storage 114, a display 116, and a communication interface 117.

  The controller 108 controls control lines 127a-127g for the ion source 102, the ion trap 104, the detector 118, the pressure control subsystem 120, the voltage source 106, the valve 129, and the optional buffer gas source 150, respectively. Connected through. Control lines 127a-127g allow controller 108 (eg, electronic processor 110 within controller 108) to issue operational commands to each component to which it is connected. Such commands may include, for example, signals to operate the ion source 102, the ion trap 104, the detector 118, the pressure regulation subsystem 120, the valve 129, and the buffer gas source 150. The commands to operate the various components of the analyzer 100 can include commands to cause the voltage source 106 to apply an electrical potential to these components. For example, to operate the ion source 102, the controller 108 can send a command to the voltage source 106 to apply a potential to the electrodes of the ion source 102. As another example, to activate the ion source 104, the controller 108 can send a command to the voltage source 106 to apply a potential to the electrodes of the ion trap 104. As yet another example, to activate detector 118, controller 108 can send an instruction to voltage source 106 to apply a potential to the detection elements of detector 118. The controller 108 also signals (eg, via the voltage source 106) a pressure regulation subsystem 120 to control the gas pressure in the various components of the analyzer 100 and the gas particles into the sample inlet. A signal can be sent to valve 129 (e.g., via voltage source 106) to be introduced into analyzer 100 via 124.

  In addition, controller 108 can receive signals from each component of analyzer 100 via control lines 127a-127g. For example, such signals may include information regarding the operating characteristics of ion source 102 and / or ion trap 104 and / or detector 118 and / or pressure regulation subsystem 120. Controller 108 may also receive information regarding the ions detected by detector 118. This information can include the ion current measured by detector 118, which relates to the abundance of ions with a particular mass to charge ratio. This information may also include information regarding the voltage applied to the electrodes of the ion trap 104, as the particular ion abundance is measured by the detector 118. These applied voltages are related to the value of the mass to charge ratio of these ions. By correlating this voltage information to the measured abundance information, controller 108 can determine the abundance of ions as a function of mass-to-charge ratio, using this information in the form of a mass spectrum using display 116 Can be presented.

  The voltage source 106 is connected to the ion source 102, the ion trap 104, the detector 118, the pressure adjustment subsystem 120, and the controller 108 through control lines 126a to 127e, respectively. The voltage source 106 supplies potential and power to each of these components via control lines 126a-e. Voltage source 106 sets a reference potential that corresponds to an electrical ground at a relative voltage of 0 volts. The potential applied by the voltage source 106 to the various components of the analyzer 100 is referenced to this ground potential. In general, voltage source 106 is configured to apply positive and negative potentials to the reference ground potential to the components of analyzer 100. By applying different potentials to the components (eg, to the electrodes of the components), electric fields of different symbols are generated within the components to move the ions in different directions. Accordingly, by applying an appropriate potential to the components of the analyzer 100, the controller 108 can control movement of ions inside the analyzer 100 (via the voltage source 106).

  The ion source 102, the ion trap 104, and the detector 118 are connected such that a gas path 128, which is an internal path for gas particles and ions, extends between these components. A sample inlet 124 and a pressure regulation subsystem 120 are also connected to the gas path 128. An optional buffer gas source 150, if provided, is also connected to the gas path 128. Some parts of gas path 128 are schematically illustrated in FIG. 1A. In general, gas particles and ions can move in any direction in the gas path 128, and the direction of movement can be controlled by the configuration of the analyzer 100. For example, by applying appropriate potentials to the ion source 102 and the electrodes of the ion trap 104, ions generated in the ion source 102 can be directed to flow from the ion source 102 into the ion trap 104.

  FIG. 1B is a partial cross-sectional view of mass spectrometer 100. As shown in FIG. 1B, output aperture 130 of ion source 102 is coupled to input aperture 132 of ion trap 104. Further, an output aperture 134 of ion trap 104 is coupled to an input aperture 136 of detector 118. As a result, ions and gas particles can flow in any direction between the ion source 102, the ion trap 104, and the detector 118. During operation of the analyzer 100, the pressure regulation subsystem 120 operates to reduce the gas pressure in the gas path 128 to a value below atmospheric pressure. As a result, gas particles to be analyzed enter the sample inlet 124 from the environment surrounding the analyzer 100 (e.g., the environment outside the housing) and enter the gas path 128. Gas particles entering the ion source 102 through the gas path 128 are ionized by the ion source 102. These ions propagate from the ion source 102 to the ion trap 104 where they are trapped by the electric field formed when the voltage source 106 applies an appropriate potential to the electrodes of the ion trap 104.

  The trapped ions circulate in the ion trap 104. To analyze the circulating ions, voltage source 106 changes the amplitude of the radio frequency trapping field applied to one or more electrodes of ion trap 104 under the control of controller 108. The change in amplitude occurs repeatedly, defining the sweep frequency of the ion trap 104. As the amplitude of the electric field changes, ions with a particular mass-to-charge ratio fall out of the orbit and some are ejected from the ion trap 104. The ejected ions are detected by the detector 118, and information on the detected ions (for example, the measured ion current from the detector and the voltage applied to the ion trap 104 when the specific ion current is measured) It is sent to the controller 108.

  The sample inlet 124 is positioned in FIGS. 1A and 1B such that gas particles enter the ion trap 104 from the environment outside the housing 122, but more generally, the sample inlet 124 is also positioned elsewhere it can. For example, FIG. 1C shows a partial cross-sectional view of the analyzer 100 with the sample inlet 124 positioned such that gas particles enter the ion source 102 from the environment outside the housing 122. In addition to the configuration shown in FIG. 1C, the sample inlet 124 can be located anywhere along the gas path 128 provided that the location allows the gas particles to enter the gas path 128 from the environment outside the housing 122.

  Communication interface 177 may generally be a wired or wireless (or both) communication interface. Controller 108 may be configured to communicate with a wide variety of devices, including remote computers, cell phones, and surveillance and security scanners, via communication interface 177. Communication interface 177 may be configured to transmit and receive data via various networks including, but not limited to, Ethernet networks, wireless WiFi networks, cellular networks, and Bluetooth wireless networks. The controller 108 communicates with the remote device using the communication interface 177 to record various information including the operation and configuration settings of the analyzer 100, record mass spectra of known substances, risks associated with particular substances, objects Information about the substance of interest, including the type of compound to which the substance belongs, and / or the spectral characteristics of the known substance. This information can be used by controller 108 to analyze sample measurements. Additionally, the controller 108 can transmit information to the remote device, including a warning message when a particular substance (eg, dangerous substance and / or explosive) is detected by the analyzer 100.

The mass spectrometers disclosed herein are compact and capable of low power operation. To achieve compact size and low power operation, various analyzer components, including the ion source 102, ion trap 104, detector 118, pressure regulation subsystem 120, and voltage source 106, Carefully designed and configured to minimize space requirements and power consumption. In conventional mass spectrometers, the vacuum pump used to achieve low internal operating pressures (eg, 1 × 10 ^-3 Torr or much lower) becomes large and consumes significant amounts of power. For example, to achieve such pressures, conventional mass spectrometers typically have one roughing pump that rapidly lowers the internal system pressure from atmospheric pressure to about 0.1-10 Torr, and 10 Torr to the internal system pressure. A series of two or more pumps are used, including one or more turbomolecular pumps that lower the pressure to the desired internal operating pressure. The roughing pump and the turbo molecular pump are both mechanical pumps that require a significant amount of power to operate. Roughing pumps (which may include, for example, piston pumps) typically generate significant mechanical vibrations. Turbo molecular pumps are typically both sensitive to vibration and mechanical shock, and have high rotational speeds to produce near gyroscope effects. As a result, conventional mass spectrometers have sufficient power supplies to meet the power consumption requirements of these vacuum pumps and isolation mechanisms (eg, vibration isolation and / or rotation) to ensure the continuous operation of these pumps. Isolation mechanism). A conventional mass spectrometer may be required not to move an internal turbo molecular pump during operation, as it may break the pump. As a result, the combination of vacuum pumps and power supplies used in conventional mass spectrometers make them large, heavy and can not be moved.

  In contrast, the mass spectrometers and methods disclosed herein are compact and portable, yet achieve low power operation. These properties are achieved, in part, by omitting the turbo molecules, roughing and other large mechanical pumps that are commonly provided in conventional analyzers. Instead of these large pumps, a small, low power single mechanical pump is used to control the gas pressure in the mass spectrometer system. The single mechanical pump used in the mass spectrometer system disclosed herein can not reach as low a pressure as a conventional turbomolecular pump. As a result, the systems disclosed herein operate at higher internal gas pressures than conventional mass spectrometers.

  As discussed in more detail below, operation at higher pressures generally reduces the resolution of the mass spectrometer due to collision-induced line broadening and charge exchange between molecular fragments. The term "resolution" is defined as the full width half maximum (FWHM) of the measured mass peak. The resolution of a particular mass spectrometer measures the FWHM for all peaks appearing within the mass-to-charge ratio range of 100-125 amu, and corresponds to a single peak (eg, a close pair of two or more peaks) Peak width is determined by selecting as the resolution the maximum FWHM corresponding to In order to determine this degree of decomposition, chemicals having a known mass spectrum such as toluene can be used.

  While the resolution of mass spectrometers may decrease when operating at higher pressures, the mass spectrometers disclosed herein do not affect the utility of the analyzer when the resolution is reduced. Is configured as. In particular, when the chemical of interest is scanned using a spectrometer, the mass spectrometers disclosed herein are not mass resolved spectra of molecular ions as they are usually done in conventional mass spectrometers. The meter is configured to report information related to the identity of the substance to the user. In some embodiments, the algorithm used in the mass spectrometers disclosed herein compares the measured ion fragmentation pattern to a known fragmentation pattern to determine the identity and / or the object of interest. Information such as one or more types of compounds to which the substance In some embodiments, these algorithms can include specialized systems that identify information regarding the identity of the substance of interest. For example, digital filters can be used to look for features in the measured spectrum of a substance of interest, which substance matches or matches a specific target substance based on the presence or absence of those features in the spectrum Can be identified as

  When the controller 108 performs the above analysis, the low resolution due to operation at high pressure can be compensated by the system disclosed herein. That is, if a reliable correspondence between the measured fragmentation pattern and the reference information can be achieved, the degradation of resolution due to high pressure operation is almost negligible to the user of the mass spectrometer disclosed herein. It is. Thus, while the mass spectrometers disclosed herein operate at higher pressures than conventional mass spectrometers, it allows the user to identify the substance rather than examining the ion fragmentation pattern of the substance of interest in detail. Maintains utility in a wide range of security scan, medical diagnostics, laboratory analysis, etc. of primary interest, where the user is not highly trained in interpreting mass spectra.

  By using a single small mechanical pump, the weight, size and power consumption of the mass spectrometers disclosed herein are significantly reduced compared to conventional mass spectrometers. Thus, the mass spectrometer disclosed herein is equipped with a small mechanical pump and internal gas pressure (gas path 128, ion source 102 connected to gas path 128, ion trap 104, detector 118). Gas pressure) between 100 mTorr and 100 Torr (eg, between 100 mTorr and 500 mTorr, between 500 mTorr and 100 Torr, between 500 mTorr and 10 Torr, between 500 mTorr and 50 Torr, and 100 A pressure regulation subsystem 120 maintained between millitorr and 1 torr). In some embodiments, the pressure control subsystem is configured to have an internal gas pressure above 100 mTorr (e.g., above 500 mTorr, above 1 Torr, above 10 Torr, 20 Torr) of the mass spectrometers disclosed herein. To be maintained).

  At the pressure described above, the mass spectrometers disclosed herein detect ions with a resolution of 10 amu or better. For example, in some embodiments, the resolution of the mass spectrometers disclosed herein is 10 amu or better (eg, 8 amu or better), as determined above. , 6 amu or better, 5 amu or superior, 4 amu or superior, 3 amu or superior, 2 amu or superior, 1 amu or better Is better). In general, any of these resolutions can be achieved at any of the pressures described above using the mass spectrometers disclosed herein.

  In addition to the pump, pressure regulation subsystem 120 can include various other components. In some embodiments, pressure regulation subsystem 120 includes one or more sensors. The one or more sensors can be configured to measure the pressure of the gas in a fluid line, such as, for example, the gas path 128, to which the pressure adjustment subsystem 120 is connected. The measured gas pressure can be sent to the pump and / or controller 108 in the pressure regulation subsystem 120 and can be displayed on the display 116. In some embodiments, pressure adjustment subsystem 120 can include one or more valves, apertures, sealing members, and / or other elements for fluid processing such as fluid lines.

  To ensure that this pressure control subsystem functions efficiently to control the internal pressure of the mass spectrometers disclosed herein, the internal volumes of these analyzers (eg, pumped by the pressure control subsystem) The volume) is considerably reduced compared to the internal volume of a conventional mass spectrometer. The reduced internal volume has the added benefit of reducing the overall size of the mass spectrometers disclosed herein, which are compact and portable, allowing one-handed operation by the user. become.

As shown in FIGS. 1B and 1C, the internal volume of the mass spectrometer disclosed herein includes the internal volumes of the ion source 102, the ion trap 104, and the detector 118, as well as the region between these components. More generally, the internal volume of the mass spectrometer disclosed herein corresponds to the volume of the gas path 128, ie the volume of all connected spaces in the mass spectrometer 100 where gas particles and ions can circulate. In some embodiments, the internal volume of the mass spectrometer 100 is less than or equal to 10 cm ³ (eg, less than or equal to 7.0 cm ^3, less than or equal to 5.0 cm ^3, less than or equal to 4.0 cm ^3, less than or equal to 3.0 cm ^3, less than or equal to 2.5 cm ³ , 2.0 cm ³ Hereinafter, it is 1.5 cm ³ or less and 1.0 cm ³ or less).

  In some embodiments, the mass spectrometers disclosed herein are fully integrated on a single support base. FIG. 1D is a schematic view of one embodiment of a mass spectrometer 100 with all its components integrated on a single support base 140. As shown in FIG. 1D, the ion source 102, the ion trap 104, the detector 118, the controller 108, and the voltage source 106 are respectively attached to the support base 140 and electrically connected. The support base 140 is a printed circuit board and includes control lines extending between components of the analyzer 100. Thus, for example, voltage source 106 may be a control line (e.g., a control line) integrated into support base 140 to ion source 102, ion trap 104, detector 118, controller 108, and pressure regulation subsystem 120. Power is supplied via 126a-127e). Further, the ion source 102, the ion trap 104, the detector 118, the pressure adjustment subsystem 120, and the voltage source 106 respectively have control lines (for example, control lines 127a to 127e) incorporated in the support base 140. The controller 108 is connected to the controller 108 via the support base 140 to transmit and receive electrical signals to each of these components.

  Integration on a single support base, such as a printed circuit board, provides many important advantages. The support base 140 provides a stable platform to the components of the analyzer 100 to ensure that each component is attached stably and safely, and the components break when the analyzer 100 is handled coarsely. Reduce the possibility of Furthermore, mounting all the components on a single support base simplifies manufacture of the analyzer 100 as the support base 140 provides a repeatable template for positioning and connection to these various components. Be done. In addition, all control lines are integrated into the support base, and both power and control signals are transmitted between the components through the support base 140 to maintain the integrity of the electrical connection between the components. . That is, such connections are less susceptible to wear and / or breakage than connections formed by individual wires extending between components.

  Furthermore, by integrating the components of the analyzer 100 on a single support base, the analyzer 100 has a compact form factor. In particular, the maximum dimension of the support base 140 (e.g. the maximum linear distance between any two points on the support base 140) is 25 cm or less (e.g. 20 cm or less, 15 cm or less, 10 cm or less, 8 cm or less, 7 cm or less, 6 cm or less).

  As shown in FIG. 1D, support base 140 is attached to housing 122 using attachment pins 145. In some embodiments, the mounting pins 145 isolate the support base 140 (and the components attached to the support base 140) from mechanical impact. For example, the mounting pin 145 can include an impact absorbing material (eg, a compliant material such as soft rubber) to buffer the support base 140 from mechanical impact. As another example, a grommet or spacer formed of shock absorbing material may be disposed between the support base 140 and the housing 122 to cushion the support base 140 against mechanical impact.

  In some embodiments, the mass spectrometers disclosed herein include a pluggable and replaceable module in which a plurality of system components are integrated. FIG. 1E is a schematic view of one embodiment of a mass spectrometer 100 including a pluggable and replaceable module 148 and a support base 140 configured to receive the module 148. The ion source 102, the ion trap 104, the detector 118, and the sample inlet 124 are each integrated into a module 148.

  Module 148 also includes a plurality of electrodes 142 that extend outwardly from the module. Within module 148, electrodes 142 are connected to each of the components of this module, such as, for example, ion source 102, ion trap 104, and detector 118.

  Also shown in FIG. 1E is a support base 140 (eg, a printed circuit board) on which the controller 108, the voltage source 106, and the pressure regulation subsystem 120 are attached. The support base 140 includes a plurality of electrodes 144 configured to removably engage and disengage the electrodes 142 of the module 148. In some embodiments, for example, electrode 142 is a pin and electrode 144 is a socket configured to receive electrode 142. Alternatively, the electrodes 144 may be pins and the electrodes 142 may be sockets configured to receive the pins. With the electrodes 142 of the module 148 aligned with the corresponding electrodes 144 of the support base, the module 148 can be connected to the support base 140 by applying a force in the direction indicated by the arrow in FIG. The support base 140 can be detachably connected or disconnected. The module 148 can be separated from the support base 140 by applying a force in the opposite direction to the arrow.

  The electrodes 144 of the support base 140 are connected to the controller 108 and the voltage source 106 as shown in FIG. 1E. Once the electrodes 142 and 144 are connected, the controller 108 can transmit and receive signals to and from each component integrated within the module 148, as described above in connection with the control line 127. Additionally, voltage source 106 can provide power to each component integrated within module 148 as described above in connection with control line 126.

  Pressure regulation subsystem 120 attached to support base 140 is connected to manifold 121 via conduit 123. When module 148 is connected to support base 140, manifold 121 including one or more apertures 125 is positioned on support base 140 such that a sealed fluid connection is established between manifold 121 and module 148. Ru. In particular, a fluid connection is established between the apertures 125 of the manifold 121 and the corresponding apertures of the module 148 (not shown in FIG. 1E). The apertures of module 148 may be formed in the wall of ion source 102, ion trap 104, and / or detector 118. Once this sealed fluid connection is established, pressure regulation subsystem 120 can control the gas pressure within the components of the module by pumping gas particles out of the 148 module through manifold 121.

  Other configurations of module 148 are also possible. In some embodiments, detector 118 is not part of module 148 and is instead attached to support base 140. In such a configuration, when module 118 is connected to support base 140, detector 118 is positioned on support base 140 such that a sealed fluid connection is provided between ion trap 104 and detector 118. Once the sealed fluid connection is established, circulating ions in the ion trap 104 can be evacuated from the trap and can be detected using the detector 118, and the pressure regulation subsystem 120 can be further detected in the detector 118. It is possible to maintain low gas pressures (e.g. between 100 mTorr and 100 Torr).

  In some embodiments, pressure regulation subsystem 120 can be integrated into module 148. For example, pressure regulation subsystem 120 can be attached to the lower surface of ion trap 104 and connected directly to gas path 128 in module 148. Pressure adjustment subsystem 120 may also be electrically connected to the electrodes of module 148. When module 148 is connected to support base 140, pressure regulation subsystem 120 can send and receive electrical signals between controller 108 and voltage source 106 via electrodes 142.

  The modular configuration of mass spectrometer 100 shown in FIG. 1E provides several advantages. For example, during operation of mass spectrometer 100, some components may be contaminated by residue of the analyte. For example, the residue of the analyte may stick to the walls of the ion trap 104, reducing the efficiency with which the ion trap 104 separates ions, and may adversely affect the analysis of other materials. By integrating the ion trap 104 into the module 148, if the ion trap 104 becomes contaminated, the entire module 148 can be replaced easily and quickly, and the mass spectrometer 100 can be put into operation by the untrained user. It is guaranteed that you can get it back quickly. Similarly, if either the ion trap 104 or the detector 118 is contaminated or malfunctioning, the module 148 can be easily replaced by the user of the analyzer 100 to return the analyzer 100 to operation.

  The modular configuration shown in FIG. 1E ensures that the analyzer 100 is compact and portable. In some embodiments, for example, the maximum dimension of support base 148 (the maximum linear distance between any two points on module 148) is 10 cm or less (e.g., 9 cm or less, 8 cm or less, 7 cm or less, 6 cm) Or less, 5 cm or less, 4 cm or less, 3 cm or less, 2 cm or less, 1 cm or less).

  Modules 148 that have degraded functionality (eg, modules contaminated with sample particles attached to the ion source 102, ion trap 104, and / or the inner wall of the detector 118) can be regenerated and reused. In some embodiments, the module can be heated when installed in the analyzer 100 to return the module 148 to normal operation. Heating can be performed by a heating element 127 attached to the support base 140. When module 148 is connected to support base 140, as shown in FIG. 1E, heating element 127 is one or more components of module 148 (eg, ion source 102, ion trap 104, and detector 118). The heating element 127 is positioned on the support base 140 so as to contact the

  The controller 108 can be configured to activate the heating element 127 by directing the voltage source 106 to apply an appropriate potential to the heating element 127. The start of heating and the temperature and duration of heating can be controlled by the user of the analyzer 100, for example, by operating the control means of the display 116 and / or inputting user configuration settings into the memory 114. In some embodiments, controller 108 may be configured to automatically determine when it is appropriate to play module 148. For example, the controller 108 can monitor the detected ion current for a certain period of time, for example, within a specific period (for example, 1 hour or more, 5 hours or more, 10 hours or more, 24 hours or more, 2 days or more, 5 days or more, 10 days If the ion current decreases by more than a threshold amount (eg, 25% or more, 50% or more, 60% or more, 70% or more), the controller 108 determines that the module 148 needs to be regenerated.

  The heating element 127 is attached to the support base 140 in FIG. 1E, but other configurations are possible. In some embodiments, for example, heating element 127 is part of module 148 and directly contacts some or all of the components of module 148 (eg, ion source 102, ion trap 104, and detector 118) It can be attached as

  In some embodiments, module 148 can be removed from analyzer 100 for regeneration. For example, if the functionality of module 148 appears degraded (eg, at the discretion of the user of analyzer 100 or at the automated determination by controller 108 using the criteria described above), module 148 may It can be removed from and heated to return to its normal operating condition. The heating can be performed in a variety of ways, including heating in a general purpose furnace. In some embodiments, analyzer 100 can include a dedicated plug-in heater that includes a slot configured to receive module 148. When a module is inserted into this slot and the heater is activated, the module is heated and its function is restored.

  Although the ion source 102, ion trap 104, and detector 118 are generally configured to detect and identify a wide variety of chemicals, in some embodiments, these components may be of a particular type. Are specialized to detect substances. In some embodiments, the ion source 102 can be specifically configured for use with a particular substance. For example, different potentials can be applied to the electrodes of the ion source 102 to generate positive or negative ions from the gas particles. In addition, the magnitude of the potential applied to the electrodes of the ion source 102 can be varied to control the efficiency with which a particular substance is ionized. In general, different substances have different ionization affinities depending on their chemical structure. By adjusting the polarity and potential difference between the electrodes of the ion source 102, the ionization of various substances can be carefully controlled.

  In some embodiments, the ion trap 104 can be specifically configured for use with a particular material. For example, the internal dimensions (eg, the inner diameter) of the ion trap 104 can be selected to be advantageous for the capture and detection of ions with higher mass to charge ratios.

  In some embodiments, the internal gas pressure in one or more of the ion source 102, ion trap 104, and detector 118 advantageously favors softer or harder ionization mechanisms or positive or negative ion production. You can choose to be In addition, the magnitude and polarity of the potential applied to the ion source 102 and the electrodes of the ion trap 104 can be selected to favor a particular ionization mechanism. As mentioned above, different substances may ionize more efficiently (e.g. by one mechanism) in one method than in another, which has an affinity for different ionizations. By adjusting the gas pressure in the analyzer 100 and the potentials applied to the various electrodes, the analyzer can be adapted, in particular to be able to detect various substances and substance types. Furthermore, by adjusting the geometry of the ion trap 104 and / or the potential applied to its electrodes, the mass window of the ion trap 104 (eg, the ion mass to charge ratio that can be maintained in a circulating trajectory within the ion trap 104) Range) can be selected.

  In some embodiments, the ion source 102 can include a particular type of ionizer that is specialized for a particular type of material. For example, ionization sources based on glow discharge ionization, electrospray mass ionization, capacitor discharge ionization, dielectric barrier discharge ionization, and any of the other types of ionizers disclosed herein can be used with ion source 102.

  In some embodiments, detector 118 can be specialized for a particular type of detection task. For example, detector 118 can be any of the one or more detectors disclosed herein. These detectors comprise, in the detector 118, a plurality of detection elements, such as a plurality of Faraday cup detectors as will be described later, in a specific and / or optional configuration, for example in the form of an array. It can be arranged. In addition to specializing for the detection of specific substances, the detector 118 can be specialized for use with a specific type of ion source and ion trap. For example, the arrangement and type of detection elements in detector 118 can be selected to correspond to the arrangement of ion chambers in ion trap 104, particularly when ion trap 104 includes multiple ion chambers.

  In some embodiments, one or more inner surfaces (eg, of the ion source 102 and / or the ion trap 104 and / or the detector 118) of the module 148 have one or more coatings and / or surface treatments Can be included. These coatings and / or surface treatments can be adapted for specific applications including detection of specific types of substances, operation within specific gas pressure ranges, and / or operation at specific applied potentials. An example of a coating and / or surface treatment that can be used to make module 148 specific to a particular substance and / or application is Teflon® (more generally, a fluoropolymer coated), anodized coating , Nickel and chromium.

  Other components of module 148 can also be adapted to detect specific substances or several types of substances. For example, the sample inlet 124 may be a filter that allows only certain types of material to pass into the analyzer 100 or, similarly, to delay the passage of certain substances into the analyzer as compared to the passage of other substances. For example, the filter 706) of FIG. 7B, which will be described later, can be provided. In some embodiments, for example, the filter may be a HEPA filter (or similar type of filter) that removes solid particles such as dust particles and particles of micron size from the flow of gas particles entering the sample inlet 124 Can be included. In some embodiments, the filter can include a molecular sieve based filter that removes water vapor from the flow of gas particles entering the sample inlet 124. Both of these types of filters do not filter atmospheric gas particles (e.g., nitrogen and oxygen molecules) and allow atmospheric gas particles to pass through and enter gas path 128 of analyzer 100. With respect to a filter such as filter 706 which does not remove or filter atmospheric gas particles as referred to in the present disclosure, it is to be understood that the filter passes at least 95% or more of the atmospheric gas particles in contact therewith.

  Thus, in some embodiments, mass spectrometer 100 can include a number of replaceable modules 148. Some of these modules may be identical and can serve as direct substitutes for each other (e.g., in case of contamination etc). Other modules can be configured for various modes of operation. For example, multiple replaceable modules 148 can be configured to detect different types of substances. The user operating the analyzer 100 can select a module suitable for a particular type of substance and plug the selected module into the support base 140 before starting the analysis. To analyze another type of material, the user may separate this first module from the support base 140, select a new module, and plug the new module into the support base 140. As a result, reconfiguration of the components of mass spectrometer 100 for various different applications is quick and easy. The module can also be specifically configured for different types of measurements (eg, different ionization methods, different capture and / or ejection potentials applied to the electrodes of the ion trap 104, and / or different detection methods). In general, each of the large number of replaceable modules 148 can include any of the optional features disclosed herein. Thus, some of these modules can be different based on the ion source, some of these modules can be different based on the ion trap, and some of these modules can be different based on the detectors. Some modules may differ from one another based on two or more of these components.

  In some embodiments, module 148 can be secured to support base 140 using one or more attachment mechanisms. Referring to FIG. 1F, module 148 includes a first attachment mechanism 195 in the form of an extension member that engages a second attachment mechanism 197 on support base 140. In some embodiments, the extension member 195 can be positioned on the support base 140 and a complementary attachment mechanism is included in the module 148. In some embodiments, the attachment mechanism 195 may be a cam in rotational engagement with the attachment mechanism 197, the attachment mechanism 197 including, for example, a recess configured to receive the cam. In some embodiments, one or more sealing members 193 (e.g., O-rings, gaskets, and / or other sealing members) made of soft material such as rubber and / or silicon are disposed to support module 148 and The connection with the base 140 can be sealed.

  In some embodiments, the attachment mechanisms 195 and 197 can be keyed so that the module 148 is connected to the support base 140 in only a single orientation. The keying of these attachment mechanisms has the advantage of preventing the user from attaching the module 148 in the wrong orientation.

  Other attachment mechanisms can also be used in some embodiments. For example, support base 140 and / or module 148 can include clamps 199 that secure module 148 to support base 140. One or more clamps can be used. Additionally, clamps may be used in addition to other attachment mechanisms.

  The following sections describe the various components of mass spectrometer 100 in more detail, and also describe the various operating modes of mass spectrometer 100.

II. Ion Source Generally, the ion source 102 is configured to generate electrons and / or ions. If the ion source 102 generates ions directly from the gas particles to be analyzed, then these ions are transferred from the ion source 102 to the ion trap 104 by appropriate potentials applied to the ion source 102 and the electrodes of the ion trap 104. Be moved. Depending on the magnitude and polarity of the potential applied to the electrodes of the ion source 102 and the chemical structure of the gas particles being analyzed, the ions generated by the electrodes of the ion source 102 can be positive ions or negative ions. In some embodiments, electrons and / or ions generated by the ion source 102 can collide with neutral gas particles to be analyzed to generate ions from these gas particles. During operation of the ion source 102, depending on the chemical structure of the gas particles being analyzed and the operating parameters of the ion source 102, various ionization effects may occur simultaneously in the ion source 102.

  Operating at higher internal gas pressures than conventional mass spectrometers, the compact mass spectrometers disclosed herein can use a variety of ion sources. In particular, an ion source that is compact and requires relatively little power to operate can be used with the analyzer 100. In some embodiments, for example, the ion source 102 may be a glow discharge ionization (GDI) source. In some embodiments, ion source 102 may be a capacitor discharge ion source.

  Various other types of ion sources may be used in the analyzer 100, depending on the amount of power and size required for operation. For example, other ion sources suitable for use in the analyzer 100 include dielectric barrier discharge ion sources and thermionic emission sources. As another example, an electrospray ionization (ESI) based ion source can be used in the analyzer 100. Such ion sources include ion sources such as desorption electrospray ionization (DESI), secondary ion electrospray ionization (SESI), extraction electrospray ionization (EESI), and paper spray ionization (PSI). It is not limited to. As yet another example, an ion source based on laser desorption ionization (LDI) can be used in the analyzer 100. Such ion sources include, but are not limited to, ion sources such as electrospray assisted laser desorption ionization (ELDI) and matrix assisted laser desorption ionization (MALDI). In addition, the analyzer 100 uses an ion source based on techniques such as atmospheric solid state analysis probe (ASAP), desorption atmospheric pressure chemical ionization (DAPCI), desorption atmospheric pressure photo ionization (DAPPI) and sonic spray ionization (SSI). be able to. Ion sources based on arrays of nanofibers (eg, arrays of carbon nanofibers) are also suitable for use. Other aspects and features of the ion source described above, as well as other examples of ion sources suitable for use in the analyzer 100, are disclosed, for example, in the following publications, the entire contents of which are hereby incorporated by reference: I quote it and use it. Alberici et al., “Ambient Mass Spectrometry: Applying Mass Spectrometry to the Real World” (“Ambient mass spectrometry: bringing MS into the 'real world,'”) Analysis and Biochemical Analysis (Anal. Bioanal. Chem.) 398: 265-294 (2010); "Ambient sampling / ion mass spectrometry: application and current trends" (Harris et al., "Ambient Sampling / Ion Mass Spectrometry: Applications and Current Trends,") analysis Chem. (Anal. Chem.) 83: 4508-4538 (2011); and Chen et al., “Microionizers for Portable Mass Spectrometers Using Double-Gate Separated Vertically Aligned Carbon Nanofiber Arrays (“ A Micro Ionizer for Portable Mass Spectrometers Using Double-gated Isolated Vertically Aligned Carbon Nanofiber Arrays "), IEEE Electronic Equipment Division 58 (7): 2149-2158 (2011).

  GDI sources are particularly advantageous for use in analyzer 100 because they are compact and suitable for low power operation. However, glow discharge that occurs when using these ion sources only occurs when the gas pressure is sufficient. Typically, for example, the GDI source is limited to a gas pressure of approximately 200 mTorr or more during operation. At pressures below 200 mTorr, it may be difficult to maintain a steady glow discharge. As a result, GDI sources are not used in conventional mass spectrometers operating at pressures below 1 mTorr. However, as the mass spectrometers disclosed herein operate at gas pressures between 100 mTorr and 100 Torr, a GDI source can be used.

  FIG. 2A shows an example of a GDI source 200 that includes a front electrode 210 and a back electrode 220. These two electrodes 210 and 220 form a GDI chamber 230 together with the housing 122. In some embodiments, GDI source 200 can also include a housing surrounding the electrodes of the ion source. For example, in the embodiment shown in FIG. 2B, GDI chamber 230 comprises a separate housing 232 that encloses electrodes 210 and 220. The housing 232 is secured or attached to the housing 122 via a fixation element 250 (eg, clamps, screws, screw components, or other types of fasteners).

  As shown in FIGS. 2A and 2B, the front electrode 210 is provided with an aperture 202 through which the gas particles to be analyzed enter the GDI chamber 230. As used herein, the term "gas particle" refers to gas atoms, molecules, or aggregated molecules that exist as discrete entities in the gaseous state. For example, if the substance to be analyzed is an organic compound, the gas particles of this substance are the individual molecules of this substance in the gas phase.

  The aperture 202 is surrounded by an insulating tube 204. In FIGS. 2A and 2B, the aperture 202 is connected to the sample inlet 124 (not shown), and the gas particles to be analyzed are GDI chamber due to the pressure difference between the atmosphere outside the analyzer 100 and the GDI chamber 230. Retracted into 230. In addition to the gas particles to be analyzed, atmospheric gas particles are also drawn into the GDI chamber 230 by this pressure difference. As used herein, the term "atmospheric gas particles" refers to atoms or molecules of gas in air such as molecules of oxygen gas or nitrogen gas.

  In some embodiments, additional gas particles can be introduced into the GDI source 200 to help generate electrons and / or ions in the ion source. For example, as described above in connection with FIG. 1A, the analyzer 100 can include a buffer gas source 150 connected to the gas path 128. Buffer gas particles from the buffer gas source 150 may be introduced directly into the GDI source 200 or may be introduced into another part of the gas path 128 and diffused into the GDI source 200. Such buffer gas particles can include nitrogen molecules and / or noble gas atoms (eg, He, Ne, Ar, Kr, Xe). Some of the buffer gas particles can be ionized by electrodes 210 and 220.

  Alternatively, in some embodiments, the mixture of gas particles to be analyzed and gas molecules comprising atmospheric gas particles is the only gas particle introduced into the GDI source 200. In such embodiments, only the gas particles to be analyzed can be ionized in the GDI chamber 230. In some embodiments, both the gas particles to be analyzed and the introduced atmospheric gas particles can be ionized in the GDI chamber 230.

  2A and 2B, the apertures 202 are located at the center of the front electrode 210, but more generally, the apertures 202 can be located at various locations of the GDI source 200. For example, the aperture 202 can be disposed on the sidewall of the GDI chamber 230 where it is connected to the sample inlet 124. Furthermore, as mentioned above, in some embodiments, the sample inlet 124 is drawn such that the gas particles to be analyzed are drawn directly into another component of the analyzer 100, such as the ion trap 104 or the detector 118. Positioning is possible. As the gas particles are drawn into components other than the ion source 102, the gas particles diffuse through the gas path 128 into the ion source 102. Alternatively or additionally, if the gas particles to be analyzed are drawn directly into a component such as ion trap 104, ion source 102 can generate ions and / or electrons, which are analyzed in ion trap 104. Collide with the gas particles to generate ions directly from the gas particles in the ion trap 104.

  Thus, depending on where the gas particles to be analyzed are introduced into the analyzer 100 (e.g., the location of the sample inlet 124), ions may be generated from the gas particles at a variety of different locations. Ions can be generated directly in the ion source 102, and the generated ions can be moved into the ion trap 104 by applying appropriate potentials to the ion source 102 and the electrodes of the ion trap 104. Ions can also be generated within the ion trap 104, where charged particles such as ions (eg, buffer gas ions) and electrons generated by the ion source 102 enter the ion trap 104 and collide with the gas particles being analyzed. In general, ions can be generated simultaneously at multiple locations (e.g., at both the ion source 102 and the ion trap 104) and all generated ions are eventually trapped within the ion trap 104. Although the descriptions in this section primarily focus on direct ion generation from the gas particles of interest in the ion source 102, the aspects and features disclosed herein are other features of the analyzer 100. It is also generally applicable to secondary ion generation from the gas particles of interest in the element.

  Various different spacings can be used between electrode 210 and back electrode 220. In general, the generation efficiency of ions includes many things including the potential difference between the electrodes 210 and 220, the gas pressure in the GDI source 200, the distance between the electrodes 210 and 220, and the chemical structure of the gas particles to be ionized It is decided by the factor of Typically, the distance 234 is relatively small to ensure that the GDI source 200 is compact. In some embodiments, the distance 234 between the electrode 210 and the electrode 220 is 1.5 cm or less (eg, 1 cm or less, 0.75 cm or less, 0.5 cm or less, 0.25 cm or less, 0.1 cm or less).

  The gas pressure in GDI chamber 230 is generally regulated by pressure regulation subsystem 120. In some embodiments, the gas pressure in GDI chamber 230 is approximately the same as the gas pressure in ion trap 104 and / or detector 118. In some embodiments, the gas pressure in GDI chamber 230 is different than the gas pressure in ion trap 104 and / or detector 118. Typically, the gas pressure in the GDI chamber 230 is less than or equal to 100 Torr (e.g., less than 50 Torr, less than 20 Torr, less than 10 Torr, less than 5 Torr, less than 1 Torr, less than 0.5 Torr) and / or greater than 100 mTorr (e.g. For example, 200 mTorr, 300 mTorr, 500 mTorr, 1 Torr, 10 Torr, 20 Torr or more).

  In operation, the GDI source 200 generates a self-sustaining glow discharge (or plasma) when a voltage difference is applied between the front electrode 210 and the rear electrode 220 by the voltage source 106 under the control of the controller 108. In some embodiments, this voltage difference can be 200V or more (eg, 300V or more, 400V or more, 500V or more, 600V or more, 700V or more, 800V or more) to maintain glow discharge. As mentioned above, the detector 118 detects the ions generated by the GDI source 200 and the potential difference between the electrodes 210 and 220 is adjusted by the controller 108 to adjust the rate at which the ions are generated by the GDI source 200. It can control.

  In some embodiments, as shown in FIG. 1D, GDI source 200 is directly attached to support base 140, and electrodes 210 and 220 are directly connected to voltage source 106 through support base 140. In some embodiments, as shown in FIG. 1E, GDI source 200 is part of module 148 and electrodes 210 and 220 are connected to electrode 142 of support base 148. When module 148 is inserted into support base 140, electrodes 210 and 220 are connected to voltage source 106 via electrode 144 that engages electrode 142.

  By applying a potential of different polarity to the ground potential established by the voltage source 106. GDI source 200 can be configured to operate in different ion modes. For example, during typical operation of the GDI source 200, only a portion of the gas particles are first ionized in the GDI chamber 230 by an irregular process (eg, thermal collisions). In some embodiments, an electrical potential is applied to the front electrode 210 and the rear electrode 220 such that the front electrode 210 acts as a cathode and the rear electrode 220 acts as an anode. In this configuration, positive ions generated in the GDI chamber 230 are moved toward the front electrode 210 by the electric field in the chamber. Negative ions and electrons are moved towards the back electrode 220. These electrons and ions collide with other gas particles to generate a large amount of ions. Negative ions and / or electrons exit the GDI chamber via the back electrode 220.

  In some embodiments, an appropriate electrical potential is applied to the front electrode 210 and the rear electrode 220 such that the front electrode 210 acts as an anode and the rear electrode 220 acts as a cathode. In this configuration, positively charged ions generated in the GDI source 200 exit the chamber via the back electrode 220. These positively charged ions collide with other gas particles to generate a large amount of ions.

  In some embodiments, the user interface 112 can include control means to allow the user to select any of the above mentioned ionization modes. Selection of the appropriate ionization mode may depend on the nature of the substance to be analyzed by the analyzer 100. Certain materials are more efficiently ionized as positive ions, and the mode of operation can be selected such that the back electrode 220 functions as a cathode. Positive ions generated during operation in this mode exit the GDI chamber 200 via the back electrode 220. Alternatively, certain substances are more efficiently ionized as negative ions, and the mode of operation can be selected such that the back electrode 220 functions as an anode. Negative ions generated during operation in this mode exit GDI source 200 via back electrode 220. In general, the controller 108 is configured to monitor the ion current measured by the detector 118 and to select an appropriate operating mode of the GDI source based on the ion current. Alternatively or additionally, the user of the analyzer 100 can use the control means displayed on the user interface 114 or input an appropriate configuration setting to the storage device 114 of the analyzer 100 in an appropriate operation mode. You can choose

  As ions are generated in any mode of operation and exit the GDI chamber 230 via the back electrode 220, these ions enter the ion trap 104 via the end cap electrode 304. In general, the back electrode 220 can include one or more apertures 240. The number of apertures 240 and their cross-sectional shapes are generally chosen to achieve a relatively uniform spatial distribution of ions incident on the end cap electrode 304. As ions generated within GDI chamber 230 exit the chamber through one or more apertures 240 of back electrode 220, the ions are spatially dispersed from one another by collisions and space charge interactions. As a result, the overall spatial distribution of ions exiting GDI source 200 diffuses. By selecting the appropriate number of apertures 240 with a particular cross-sectional shape, the spatial distribution of ions exiting the GDI source 200 overlaps or fills all the apertures 292 formed in the end cap electrode 304. Can be controlled. In some embodiments, additional ion optics (eg, ion lenses) can be disposed between the back electrode 220 and the end cap electrode 304 to further manipulate the spatial distribution of ions exiting the GDI source 200. However, a unique advantage of the compact ion source disclosed herein is that proper ion distribution can be obtained without placing additional elements between the back electrode 220 and the end cap electrode 304.

  In some embodiments, back electrode 220 includes a single aperture 240. The cross-sectional shape of the aperture 240 may be circular, square, square, or generally correspond to a polygon having N sides of any regular or irregular shape. In some embodiments, the cross-sectional shape of the aperture 240 may be irregular.

  In some embodiments, back electrode 220 includes two or more apertures 240. In general, the back electrode 220 can include any number of apertures, separated by any distance, as long as the back electrode 220 remains mechanically stable enough for use with the GDI source 200 (e.g., , 2 or more, 4 or more, 8 or more, 16 or more, 24 or more, 48 or more, 64 or more, 100 or more, 200 or more, 300 or more, 500 or more). 2C-2H show various embodiments of the back electrodes 220, each with a variety of different apertures 240. FIG. As shown in FIGS. 2C-2H, the back electrode 220 can be generally circular, square, or any other shape.

  FIG. 2C shows the back electrode 220 with a regular array of apertures 242. Although 25 apertures 242 are shown in FIG. 2C, more generally, any number of apertures 242 can be present. Furthermore, the apertures 242 have a circular cross-sectional shape, but more generally, apertures 242 with any regular or irregular cross-sectional shape can be used. Apertures with different cross-sectional shapes may be used with one electrode 220. In general, the size of the openings formed by the apertures 242 may be selected as desired, and different sized apertures 242 may be present in a single back electrode 220. Typically, the number of apertures formed in the back electrode 220 and the size of the apertures control the gas pressure drop of the electrodes. Thus, by selecting the aperture size and number, the target pressure drop of the back electrode 220 during operation of the mass spectrometer 100 can be achieved.

  2D-2G show further exemplary embodiments of the back electrode 220 with the openings 243, 244, 245 and 246. FIG. In FIGS. 2D-2G, the openings 243, 244, 245, and 246 may be formed by a slit (eg, a continuous opening) or a series of apertures formed in the back electrode 220 and spaced apart from one another. As shown in FIGS. 2D-2G, the openings 243, 244, 245, and 246 can be arranged to form an array of linear openings, an array of concentric circular arcs, a serpentine path, and a spiral path. However, the embodiments shown in FIGS. 2D-2G are for illustration purposes only. More generally, a wide variety of different arrangements of apertures with different cross-sectional shapes and sizes can be used in the back electrode 220.

  FIG. 2H shows an embodiment of the back electrode 220 with the apertures 247 in a hexagonal array. The hexagonal array shown in FIG. 2H and the square or square array shown in FIG. 2C are examples of the regular array of apertures that can be formed on the back electrode 220. However, more generally, the back electrode 220 can use a variety of different regular array of apertures such as, but not limited to, a circular array or a radial array.

  As shown in FIGS. 2A and 2B, the end cap electrode 304 of the ion trap 104 can also include one or more apertures 294. In some embodiments, end cap electrode 304 includes a single aperture 294 with a circular, square, rectangular, or other N-sided polygonal cross-sectional shape. In some embodiments, the aperture has an irregular cross-sectional shape.

  More generally, end cap electrode 304 can include a number of apertures 294. The types of apertures of the end cap electrodes 304, their arrangements, and the criteria for selecting particular types of apertures are generally similar to the types, arrangements, and criteria previously described in connection with the back electrode 220. Furthermore, the above description applies equally to the apertures 294 formed in the end cap electrode 304.

  As shown in FIGS. 2A and 2B, the back electrode 220 is spaced from the end cap electrode 304 by an amount 244. The space between the electrodes allows the ions coming out of the back electrode 220 to be spatially dispersed and to fill the apertures 294 formed in the end cap electrode 304 as uniformly as possible. To further facilitate uniform filling of the apertures 294, in some embodiments, the pattern of apertures 240 formed in the back electrode 220 can be matched to the pattern of apertures 294 formed in the end cap electrode 304 .

  More specifically, as shown in FIG. 2H, the pattern of apertures 247 formed in the back electrode 220 defines the cross-sectional shape of the back electrode 220. Similarly, the pattern of apertures formed in the end cap electrode 304 defines the cross-sectional shape of the end cap electrode 304. In some embodiments, the cross-sectional shapes of the back electrode 220 and the end cap electrode 304 generally match. As used herein, "generally matches" means that the relative position of at least 70% or more of the apertures formed in the back electrode 220 is the same as the relative position of the apertures formed in the end cap electrode 304. . For each aperture, its position corresponds to the position of its center of mass.

  In some embodiments, the pattern of apertures 240 formed in the back electrode 220 exactly corresponds to the pattern of apertures 294 formed in the end cap electrode 304, ie, one to one between these apertures There is a correspondence relationship between Generally, as the degree of coincidence of these apertures with the back electrode 220 and the end cap electrode 304 increases, ions exiting from the back electrode 220 will more uniformly fill the apertures 294 of the end cap electrode 304 and so on. The distance 244 to the end cap electrode 304 can be short. If the apertures between these electrodes are completely or nearly perfectly matched, then the distance 244 is zero (ie the back electrode 220 can be placed directly adjacent to the end cap electrode 304), making the GDI source 200 extremely compact Can be Furthermore, as the degree of coincidence between the apertures increases, the number of ions entering the apertures 294 can be maximized by reducing the number of ions colliding with the portion of the end cap electrode 304 between the apertures. As a result, the ion collection efficiency of the ion trap 104 is improved. Furthermore, by improving the efficiency with which ions generated by the ion source 102 are collected in the ion trap 104, the overall size of the back electrode 220 and the end cap electrode 304 can be matched to one electrode and / or the aperture. It can be reduced compared to an electrode with a non-aperture.

  In some embodiments, the back electrode 220 and the end cap electrode 304 can be formed as a single element, and ions generated by the GDI source 200 can directly enter the ion trap 104 by passing through the element. In such embodiments, the integrated back and end cap electrodes can include a single aperture or multiple apertures as described above.

  Further, in some embodiments, the end cap electrodes of ion trap 104 can function as front electrode 210 and back electrode 220 of GDI source 200. As will be described in more detail below, the ion trap 104 includes two end cap electrodes 304 and 306 disposed on opposite sides of the trap. The end cap electrode 304 can function as the front electrode 210 and the end cap electrode 306 can be the back electrode by applying an appropriate potential (eg, as described above in connection with the front electrode 210 and the back electrode 220) to these electrodes It can function as 220. Thus, in these embodiments, the ion trap 104 also functions as the glow discharge ion source 102.

  Various operating modes can be used to generate charged particles in GDI source 200. For example, in some embodiments, a continuous mode of operation can be used. FIG. 2I includes a graph illustrating one embodiment of a continuous operating mode in which a constant bias voltage 262 is applied between the front electrode 210 and the rear electrode 220 of the GDI source 200. In this mode, charged particles are generated continuously in the ion source.

  In some embodiments, GDI source 200 is configured to perform pulsing. FIG. 2I illustrates one embodiment of pulsed mode operation where a bias potential 272 is applied to the front electrode 210 and the rear electrode 220 for a period of time 272. Repeated application of the bias potential 272 defines the number of repetitions of the pulsing operation that corresponds to the inverse of the period 276 between successive pulses. In general, period 276 may be much longer (e.g., 100 times longer) than period 274 in which bias potential 272 is applied to the electrodes. In some embodiments, for example, period 274 is about 0.1 milliseconds and period 276 is about 10 milliseconds. More generally, period 274 is less than or equal to 5 milliseconds (eg, less than or equal to 4 milliseconds, less than or equal to 3 milliseconds, less than or equal to 2 milliseconds, less than or equal to 1 millisecond, less than or equal to 0.8 milliseconds, less than or equal to 0.6 milliseconds, less than or equal to 0.5 milliseconds , 0.4 milliseconds or less, 0.3 milliseconds or less, 0.2 milliseconds or less, 0.1 milliseconds or less, 0.05 milliseconds or less, 0.03 milliseconds or less), and the period 276 is 50 milliseconds or less (eg, 40 milliseconds or less, 30 or less). Ms or less, 20 ms or less, 10 ms or less, 5 ms or less).

  Ions are generated over a period 274 in which a bias potential 272 is applied to the electrodes. In some embodiments, the timing of the pulse bias potential 272 during pulse mode operation is used to generate the high voltage RF signal 482 applied to the center electrode of the ion trap 104, as described in more detail below. It can also be synchronized with the modulation signal 412. Graph 280 of FIG. 2J is a plot of modulation signal 412 used to generate RF signal 482 applied to the center electrode of ion trap 104. Comparing graph 280 with graph 270, when pulse bias potential 272 is applied to the electrodes of GDI source 200, modulation signal 412 is turned off. During this time, ions are generated in the GDI source 200. Next, the bias potential 272 is stopped and the modulation potential 282 is applied. At spacing 284, these ions are trapped and stabilized in the ion trap 104. The trapped ions are then ejected from the ion trap 104 into the detector 118 by increasing the amplitude of the potential applied to the center electrode of the ion trap 104 at an interval 286.

  Pulsed mode operation has several advantages. For example, the repetition number and duration and / or amplitude of the pulse bias potential 272 can be adapted to the amount and gas pressure of the gas particles to be analyzed present in the ion trap 104. In general, controller 108 monitors the ion current measured by detector 118, and controller 108 can adjust one or more of the parameters associated with pulsed mode operation based on the magnitude of the ion current.

  In some embodiments, for example, controller 108 can adjust the amplitude of bias potential 272. Increasing the bias potential can increase the rate at which ions are generated by the GDI source 200.

  In some embodiments, controller 108 can adjust the number of repetitions of bias potential 272. For some analytes of interest, increasing the repetition rate can increase the incidence of ions in the GDI source 200. For other analytes, decreasing the repetition rate can increase the rate of ion generation at the GDI source 200. The controller 108 can be configured to adjust the number of iterations adaptively until the ion generation rate at the GDI source 200 reaches an appropriate value.

  In some embodiments, controller 108 can be configured to adjust the duty cycle of GDI source 200. Referring to graph 270, the duty cycle of GDI source 200 indicates the ratio of period 274 during which bias potential 272 is applied to the total period 276. The controller 108 can be configured to adjust the duty cycle of the GDI source 200. For example, this duty cycle can be reduced to reduce the rate at which ions in the GDI source 200 are generated. By reducing the rate at which ions are generated, the signal-to-noise ratio of the measured ion signal is improved, and unwanted ghost peaks are removed (when stopped by measurement by the ion source 200, the GDI source 200). Peaks due to unwanted charged particles generated by the D. Alternatively, the duty cycle can be increased to increase the rate at which ions are generated at the GDI source 200.

  In some embodiments, controller 108 has a duty between 1% and 50% (eg, between 1% and 40%, between 1% and 30%, between 1% and 20%, Can be configured to adjust to values between 1% and 10%).

  Another important advantage of pulsed mode operation is that the bias potential applied between the electrodes 210 and 220 is turned off when not required, for example when the ion source 200 has already generated ions. Stopping the bias potential during most of the duty cycle of the ion source 200 can lead to a significant reduction in the amount of power required to operate the analyzer.

  Further, pulsed mode operation avoids the use of gates or shields disposed between the GDI source 200 and the detector 118. By eliminating the gates and shields commonly used in conventional mass spectrometers, considerable space is saved and the amount of power required to operate the analyzer 100 is reduced.

  In some embodiments, the operating conditions of GDI source 200 can be checked using an automatic calibration procedure. For example, the user can initiate a calibration procedure that sequentially analyzes one or more known reference samples. The phantom peaks (i.e., the peaks that should not be present in the measured spectrum) may indicate that the GDI source 200 is contaminated. For example, one of the electrodes 210 and 220 may be embedded with sticky particles or debris that can cause phantom peak detection. In some construction procedures, no sample is injected and phantom peaks are detected against analyzer noise. The determination of whether the GDI source 200 needs to be replaced may be based on the result of calibration, for example, the number and size of phantom peaks detected.

  To facilitate replacement, in some embodiments, the ion source 200 can be configured as a separate module from other components of the analyzer 100. For example, as shown in FIG. 2B, GDI source 200 can be implemented as a separate module that can be easily removed by releasing attachment element 250 from other components of analyzer 100 or from housing 122. Alternatively, the electrodes 210 and 220 can be configured to be separately removable from the GDI source 200. Removal of the electrodes 210 and 220 can be accomplished, for example, by removing the cover integral with the housing 122 adjacent the location of the electrodes. When the cover is removed from the housing 122, the exposed electrode is removable from the GDI source 200.

  In some embodiments, GDI source 200 can be cleaned instead. For example, the GDI source 200 can be cleaned by applying a potential bias corresponding to the reverse duty cycle to the electrodes 210 and 220. FIG. 2J is a graph 263 of the reverse duty cycle applied to electrodes 210 and 220 during clean processing, as bias potential 264, ie, reversed with respect to the pulse mode bias potential shown in graph 270. A constant DC potential is applied for most of the duty cycle and is interrupted only by the short potential drop of period 274. These potential drops are repeated in period 276. While not wishing to be bound by theory, it is believed that this rapid voltage change facilitates the removal of sticky particles embedded in the electrodes 210 and 220. Once it is determined that the GDI source 200 is clean (eg, using the calibration procedure described above), the GDI source 200 can be switched to normal operation (eg, pulse mode operation) to generate ions.

  In some embodiments, controller 108 may have a duty cycle between 50% and 100% at cleaning (eg, between 50% and 90%, 50% and 80%, 50% and 70%). %, And between 50% and 60%). The reverse duty cycle spans a total of 5 seconds or more (eg, 10 seconds or more, 20 seconds or more, 30 seconds or more, 40 seconds or more, 50 seconds or more, 1 minute or more, 2 minutes or more, 3 minutes or more, 5 minutes or more) It can be applied.

  If the electrodes of GDI source 200 are contaminated, other methods can be used to clean them. In some embodiments, a cleaning gas may be injected into the GDI source 200 to facilitate the removal of sticky particles of the electrodes 210 and 220. Suitable cleaning gases can include, for example, noble gases. Furthermore, in some embodiments, cleaning of the electrodes of GDI source 200 can also be facilitated by heating electrodes 210 and 220. In some embodiments, electrodes 210 and 220 can be removed from GDI source 200 and cleaned in an appropriate cleaning solution.

  The above description has focused on the measurement of phantom peaks to determine if the GDI source 200 is contaminated. More generally, other methods may be used in addition to or instead of phantom peak detection. For example, controller 108 can be configured to monitor the measurement of ion current by detector 118. If the ion signal measured by the detector 118 fluctuates or suddenly changes (eg, jumps and falls) above a threshold amount, or the average detected ion / electron signal has an attenuation below a certain threshold If so, controller 108 can automatically determine that cleaning or replacement of GDI source 200 is desired.

  Various materials can be used to form the electrodes of the ion source 102, including the electrodes 210 and 220 of the GDI source 200. In some embodiments, the electrodes of the ion source 102 can be made of materials such as copper, aluminum, silver, nickel, gold, and / or stainless steel. In general, materials in which adsorption of sticky particles is less likely to be advantageous, as such materials typically do not require frequent cleaning or replacement.

  The above description has focused on the use of GDI source 200 in analyzer 100. However, the features, design criteria, algorithms, and aspects described above apply to other types of ion sources that can be used with the analyzer 100, such as capacitor discharge sources and thermionic emission sources. In particular, a capacitor discharge source is well suited for use at the relatively high gas pressures at which the analyzer 100 operates. Thus, the above description also applies to such an ion source. For example, FIG. 2K shows an example of a capacitor discharge source 265 that includes an array of ionization sources 266. The inset of FIG. 2K shows a magnified view of a single ionization source 266 with a wire 267 and an insulation coated wire 268. FIG. When a bias potential is applied by the voltage source 106 to the line 267, a plasma discharge is generated from each of the ionization sources 266. Ions generated by the capacitor discharge source 265 enter the ion trap 104 where they are trapped and selectively ejected for detection. Additional aspects and features of the capacitor discharge source are described, for example, in US Pat. No. 7,274,015, the entire contents of which are incorporated herein by reference.

  The use of compact, closely spaced electrodes allows the overall size of the ion source 102 to be reduced. The largest dimension of the ion source 102 refers to the largest linear distance between any two points of the ion source. In some embodiments, the largest dimension of the ion source 102 is 8.0 cm or less (eg, 6.0 cm or less, 5.0 cm or less, 4.0 cm or less, 3.0 cm or less, 2.0 cm or less, 1.0 cm or less).

III. Ion Traps As described in Section I, the ions generated by the ion source 102 are trapped within the ion trap 104 where the ions are of the electric field formed by applying a potential to the electrodes of the ion trap 104. Circulate under the influence. These potentials are applied by the voltage source 106 to the electrodes of the ion trap 104 after receiving a control signal from the controller 108. In order to eject circulating ions from the ion trap 104 for detection, the controller 108 sends a signal to the voltage source 106 which modulates the amplitude of the radio frequency (RF) field in the ion trap 104 to the voltage source 106. Let Modulation of the amplitude of the RF field causes the circulating ions in the ion trap 104 to be out of orbit and exit the ion trap 104 and enter the detector 118 where they are detected.

  As described in Section I, to ensure that the mass spectrometer 100 is compact and consumes relatively small amounts of power during operation, the mass spectrometer 100 can be configured as a single compact unit in the pressure regulation subsystem 120. Adjust the internal gas pressure using only a mechanical pump. As a result, mass spectrometer 100 operates at an internal gas pressure that is higher than the internal pressure of a conventional mass spectrometer. In order to ensure that the gas particles drawn into the spectrometer 100 are rapidly ionized and analyzed, the internal volume of the mass spectrometer 100 is made considerably smaller than the internal volume of a conventional mass spectrometer. By reducing the internal volume of the analyzer 100, the pressure regulation subsystem 120 can quickly draw gas particles into the analyzer 100. Furthermore, by ensuring rapid ionization and analysis, the user of the analyzer 100 can quickly obtain information on specific substances. The small internal volume of the analyzer 100 also provides the added benefit of reducing the internal surface that is prone to contamination during operation. Conventional mass spectrometers use a variety of different mass analyzers, many of which have large internal volumes that are maintained at low pressure during operation and / or consume large amounts of power during operation. For example, some mass spectrometers use linear quadrupole mass filters, which are axially extended to provide a large internal volume, which allows mass filtering and large charge storage capacity. Some mass spectrometers use magnetic sector mass filters, which are also typically large and may consume a large amount of power to generate a mass filtering field. Conventional mass spectrometers may also use a hyperbolic ion trap, which may have a large internal volume and may be difficult to manufacture.

  In contrast to the conventional ion trap techniques described above, the mass spectrometers disclosed herein use a compact, cylindrical ion trap for capturing and analyzing ions. FIG. 3A is a cross-sectional view of one embodiment of the ion trap 104. The ion trap 104 includes a cylindrical center electrode 302, two end cap electrodes 304 and 306, and two insulating spacers 308 and 310. The electrodes 302, 304 and 306 are connected to the voltage source 106 via control lines 312, 314 and 316, respectively. The voltage source 106 is connected to the controller 108 via the control line 120e, and the controller 108 transmits a signal via the control line 127e to instruct the voltage source 106 to apply a potential to the electrode of the ion trap 104.

  In operation, ions generated by the ion source 102 enter the ion trap 104 through the aperture 320 in the electrode 304. The voltage source 106 applies a potential to the electrodes 304 and 306 to create an axial electric field (eg, symmetrical about axis 318) within the ion trap 104. This axial field axially confines the ions between the electrodes 304 and 306 to ensure that the ions do not exit the ion trap through the apertures 320 or the apertures 322 of the electrodes 306. Voltage source 106 also applies a potential to central electrode 302 to generate a radially confined electric field within ion trap 104. This radial field confines the ions radially within the internal aperture of the electrode 302.

  The presence of axial and radial electric fields in the ion trap 104 causes ions to circulate in the trap. The orbital shape of each ion is determined by a number of factors including the geometry of electrodes 302, 304, and 306, the magnitude and sign of the potential applied to the electrodes, and the mass to charge ratio of the ions. By varying the magnitude of the potential applied to central electrode 302, ions of a particular mass to charge ratio will be de-orbited within trap 104, exit the trap via electrode 306, and enter detector 118. Thus, to selectively analyze ions of different mass to charge ratios, the voltage source 106 stepwise changes the amplitude of the potential applied to the electrode 302 (under the control of the controller 108). As the amplitude of the electric field changes, ions of different mass to charge ratios are ejected from the ion trap 104 and detected by the detector 118.

  The electrodes 302, 304, and 306 of the ion trap 104 are generally formed of a conductive material such as stainless steel, aluminum, or other metals. Spacers 308 and 310 are generally formed from ceramics, Teflon, (eg, a fluoropolymer coated material), rubber, or various plastic materials.

The central openings of end cap electrodes 304 and 306, central electrode 302, and spacers 308 and 310 may have the same diameter and / or shape, or different diameters and / or shapes. For example, in the embodiment shown in FIG. 3A, the central openings of electrode 302 and spacers 308 and 310 have a circular cross-sectional shape and diameter c ₀ , and end cap electrodes 304 and 306 have a circular cross-sectional shape and diameter c _2. It has a central opening with c ₀ . As shown in FIG. 3A, the openings of the electrodes and spacers are axially aligned along the axis 318, and when the electrodes and spacers are assembled in a sandwich configuration, the openings of the electrodes and spacers are in the ion trap 104. Form a continuous axial opening to stretch.

In general, the diameter c ₀ of the central opening of electrode 302 is selected as desired to achieve a particular target resolution in selectively ejecting ions from ion trap 104 and to adjust the total internal volume of analyzer 100. do it. In some embodiments, c ₀ is approximately 0.6 mm or more (eg, 0.8 mm or more, 1.0 mm or more, 1.2 mm or more, 1.4 mm or more, 1.6 mm or more, 1.8 mm or more). Diameter c ₂ of the central opening of the end cap electrodes 304 and 306 is also to achieve a specific goal resolution when ejecting ions from the ion trap 104, and selects as desired to ensure proper containment of not ejected ions May be In some embodiments, c ₂ is approximately 0.25 mm or more (eg, 0.35 mm or more, 0.45 mm or more, 0.55 mm or more, 0.65 mm or more, 0.75 mm or more).

Also, the axial length c _{1 of} the electrode 302 and the combined aperture of the spacers 308 and 310 is also desired to ensure proper confinement of the ions and to achieve a specific target resolution when ejecting the ions from the ion trap 104 You just have to make your choice. In some embodiments, c ₁ is approximately 0.6 mm or more (eg, 0.8 mm or more, 1.0 mm or more, 1.2 mm or more, 1.4 mm or more, 1.6 mm or more, 1.8 mm or more).

It has been experimentally confirmed that the resolution of the analyzer 100 is increased when c ₀ and c ₁ are selected such that c ₁ / c ₀ exceeds 0.83. Thus, in some embodiments, c ₀ and c ₁ are such that the value of c ₁ / c ₀ is 0.8 or more (eg, 0.9 or more, 1.0 or more, 1.1 or more, 1.2 or more, 1.4 or more, 1.6 or more). It is selected.

  The relatively small size of the ion trap 104 limits the number of ions that can be simultaneously trapped within the ion trap 104 due to various factors. One such factor is the space charge interaction between ions. As the density of captured ions increases, the average spacing between captured circulating ions decreases. As these ions (all with a positive or negative charge) move closer to one another, the repulsion between these trapped ions increases.

  In order to overcome the limitations on the number of ions that can be simultaneously trapped within the ion trap 104 and to increase the ability of the analyzer 100, in some embodiments, the analyzer 100 may include an ion trap with multiple chambers it can. FIG. 3B shows a schematic view of an ion trap 104 with a plurality of ion chambers 330 arranged in a hexagonal array. Each chamber 330 functions similarly to the ion trap 104 of FIG. 3A and includes two end cap electrodes and a cylindrical central electrode. In FIG. 3B, end cap electrode 304 is illustrated with a portion of end cap electrode 306. End cap electrode 304 is connected to voltage source 106 via connection point 344, and end cap electrode 306 is connected to voltage source 106 via connection point 332.

  FIG. 3C is a cross-sectional view about the cross-sectional line AA in FIG. 3B. Each of the five ion chambers 330 along the cross-sectional line AA is illustrated. The voltage source 106 is connected to the center electrode 302 via a single connection point (not shown in FIG. 3C). As a result, by applying an appropriate potential to the electrodes 302, the voltage source 106 (under control of the controller 108) simultaneously captures ions in each chamber 330 and selects ions with selected mass-to-charge ratios. The chamber 330 can be evacuated.

  In some embodiments, the number of ion chambers 330 in the ion trap 104 can be matched to the number of apertures formed in the end cap electrode 304. As described in Section II, end cap electrode 304 can generally include one or more apertures. When the end cap electrode 304 includes a plurality of apertures, the ion trap 104 also includes a plurality of ion chambers 330, and each aperture formed in the end cap electrode 304 corresponds to a different ion chamber 330. In this manner, ions generated in the ion source 102 can be efficiently collected by the ion trap 104 and captured in the ion chamber 330. As mentioned above, the use of multiple chambers reduces the space charge interaction between the trapped ions and increases the trapping capacity of the ion trap 104. In general, the position and cross-sectional shape of the ion chamber 330 may be the same as the arrangement and shape of the apertures 240 and 294 described in Section II.

  As an example, referring to FIG. 3B, end cap electrode 304 includes a plurality of apertures arranged in a hexagonal array. Each aperture formed in the electrode 304 corresponds to the corresponding ion chamber 330, so the ion chambers 330 are also arranged in a hexagonal array.

  In some embodiments, the number, placement, and / or cross-sectional shape of the ion chambers 330 do not match the placement of the openings of the end cap electrode 304. For example, while the end cap electrode 304 comprises only one or a few apertures 294, the ion trap 304 can also include multiple ion chambers 330. The use of multiple ion chambers 330 increases the capture capability of the ion trap 104, so multiple ion chamber usage may be advantageous even if the arrangement of the ion chambers is not consistent with the arrangement of the end cap electrode 304 apertures. It can be

  Additional side features of the ion trap 104 are described in US Pat. Nos. 6,469,298, 6,762,406, and 6,933,498, the entire contents of each being incorporated herein by reference.

IV. Voltage Source Voltage source 106 provides operating power and potential to the components of analyzer 100 based on the signal transmitted by controller 108 via control line 127e. As mentioned above in Section I, the key advantages of the mass spectrometers disclosed herein are their compact size and significantly lower power consumption compared to conventional mass spectrometers. Although the analyzer 100 can generally operate with various voltage sources, it is advantageous if the voltage source 106 is highly efficient in order to reduce the power consumption of the analyzer 100 as much as possible.

  However, highly efficient voltage sources that are small in size and that generate sufficient voltage to drive the components of the analyzer 100 are not readily available commercially. FIG. 4A shows a schematic diagram of an embodiment of a high efficiency voltage source 106 configured to provide a high voltage RF signal 482 applied to the center electrode 302 of the ion trap 104. In operation, the voltage source 106 can amplify the voltage received from the power supply 440 while modifying the waveform of the high voltage RF signal 482 to be suitable for a particular mass spectral measurement.

  The design of the power supply 106 allows the analyzer 100 to operate with high power efficiency at various sweep stages of the high voltage RF signal 482. At each stage, power efficiency is defined as the ratio of input power to output power. In some embodiments, the efficiency of the power supply 106 is at least 40% (eg, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%) at all stages of voltage amplification. Can. In contrast, conventional power amplifiers (e.g., emitter follower or class A amplifiers) typically provide maximum efficiency at the highest amplification level, but at lower amplification levels there is much lower efficiency. Thus, conventional power amplifiers may be inadequate and may not be sufficient for applications requiring swept voltage amplification.

  In addition to high efficiency operation, voltage source 106 allows a relatively low power supply (e.g., a battery) to provide the power and potential needed to operate the various components of analyzer 100. As a result, the analyzer 100 has a compact form factor and is much lighter than conventional power amplifiers.

  Referring to FIG. 4A, voltage source 106 includes a proportional integral derivative (PID) control loop 420, a switch mode power supply 430, an optional linear regulator 450, a class D amplifier 460, and a resonant circuit 480. In some embodiments, various components of voltage source 106 can be integrated into a module, which can be plugged into support base 140. This allows voltage source 106 to be easily replaced with another module if it fails. Alternatively, in some embodiments, one or more components of voltage source 106 can be implemented as separate modules and are interchangeable alone. In some embodiments, some or all of the components can be attached directly to the support base 140. Because each component shown in FIG. 4A is normally commercially available at relatively low cost, voltage source 106 can be economically manufactured.

  In operation, PID control loop 420 receives modulation signal 412 from modulation signal generator 410, which may or may not be a component of voltage source 106. FIG. 4B shows an example of the modulation signal 412, in which the change in amplitude of the signal (ie the envelope) is shown as a function of time. The envelope of modulated signal 412 is generally correlated with the envelope of output high voltage RF signal 482. Based on modulated signal 412, PID control loop 420 sends control signals 422 and 422 to switch mode power supply 430 and linear regulator 450 (if present), respectively.

  Switch mode power supply 430 is configured to receive input power signal 442 from power supply 440, which may include a battery (eg, lithium ion, lithium polymer, nickel cadmium, nickel metal hydride battery). The voltage supplied by the power supply 440 is typically between about 0.5V and about 13V. As an example, this voltage is about 7.2V. The switch mode power supply 430 amplifies the input power signal 422 based on the control signal 422 to obtain a modulated voltage signal 432 that is sent to the linear regulator 450 (if present). Modulated voltage signal 432 is shown in FIG. 4C. The modulated voltage signal 432 typically has an amplitude between 0V and about 25V.

  In some embodiments, switch mode power supply 430 includes a switching regulator for efficient power amplification. In operation, the input power signal 422 may be lower than, the same as, or higher than the output voltage signal 432. This feature is advantageous when the power supply 440 is a battery. Unlike a linear power supply, switch mode power supply 430 (which is a non-linear amplifier) provides high power conversion as it switches with little or no power when switching between various amplification states. Furthermore, the switch mode power supply 430 is typically compact and lightweight for conventional power amplifiers due to the size and weight of the smaller internal transformers.

  The linear regulator 450 is optionally included in the voltage source 106. If linear regulator 150 is not present at voltage source 106, a modified voltage signal 432 is sent directly from switch mode power supply 430 to class D amplifier 460. Alternatively, if linear regulator 450 is present at voltage source 106, linear regulator 450 receives both modulated voltage signal 432 from switch mode power supply 430 and control signal 424 from PID control loop 420. .

  The linear regulator 450 functions to filter out irregularities in the correction voltage signal 432. Filtered voltage signal 442 from linear regulator 450 is received by class D amplifier 460. Typically, linear regulator 450 is a low dropout voltage regulator, where a constant low drop voltage ensures that the overall efficiency of voltage source 106 is only slightly reduced by the presence of linear regulator 450 . In some embodiments, the control signal 422 received by the linear regulator 450 is used to modify the envelope of the output voltage signal 442 to be suitable for mass spectral measurement of a particular substance.

  Reference wave generator 470 is optionally included in voltage source 106. If provided, reference wave generator 470 provides reference wave signal 472 to class D amplifier 460. Generally, reference wave signal 472 comprises a frequency in the high frequency range (e.g., from about 0.1 MHz to about 50 MHz). For example, in some embodiments, reference wave signal 472 can comprise a frequency of 1 MHz or more (eg, 2 MHz or more, 4 MHz or more, 6 MHz or more, 8 MHz or more, 15 MHz or more, 30 MHz or more).

  FIG. 4D shows an example of the reference wave signal 472. In FIG. 4D, an example of the reference wave signal 472 is a square wave. More generally, reference wave generator 470 can generate reference wave signal 472 of various different waveforms. In some embodiments, for example, reference wave signal 472 can match either a triangular waveform, a sinusoidal waveform, or a waveform close to a sinusoidal waveform.

  Class D amplifier 460 comprises a reference wave signal 472 (if reference wave generator 470 is provided) and a filtered voltage signal 442 (or correction voltage signal 432 if linear regulator 450 is not provided). Both are received and a modulated RF signal 462 is generated from these input signals. FIG. 4E shows an example of the modulated RF signal 462. In this example, the period of signal 462 is approximately 10 milliseconds. The amplitude of signal 462 varies between about 0 volts and about 30 volts. The frequency of the carrier wave of the RF signal 462 is the same as or substantially the same as the frequency of the reference wave signal 472. The envelope of the RF signal 462 (eg, shown as a dashed line in FIG. 4E) is the same as or substantially the same as the envelope of the filtered voltage signal 442 (or the modified voltage signal 432).

  FIG. 4F is a schematic diagram of an embodiment of a class D amplifier 460. Class D amplifier 460 includes a pair of transistors 441. Within class D amplifier 460, reference wave signal 472 is modulated with the envelope of filtered voltage signal 442 (or modified voltage signal 432) to generate RF signal 462.

  The RF signal 462 is received by a resonant circuit 480, also schematically illustrated in FIG. 4F. The resonant circuit 480 includes an inductor 486 and a capacitor 488. In some embodiments, the positions of inductor 486 and capacitor 488 may be interchanged with respect to the positions shown in FIG. 4F. The values of the inductance of inductor 486 and the capacitance of capacitor 488 are generally selected such that the resonant frequency of circuit 480 substantially matches the frequency of reference wave signal 472.

  In some embodiments, resonant circuit 480 comprises 60 or more (eg, 80 or more, 100 or more) Q factors. When RF signal 462 is applied to resonant circuit 480, high voltage RF signal 482 is generated at capacitor 488. In general, the waveform of the high voltage RF signal 482 is the same or substantially the same as the waveform of the RF signal 462, except that the amplitude of the high voltage RF signal 482 is much larger than the amplitude of the RF signal 462. For example, in some embodiments, the maximum amplitude of the high voltage RF signal 482 is 100V or more (eg, 500V or more, 1000V or more, 1500V or more, 2000V or more). In general, the high Q factor of resonant circuit 480 generates a voltage of large amplitude in RF signal 462.

  The combination of class D amplifier 460 and resonant circuit 480 is advantageous for a number of reasons including low power consumption and frequency regulation. A further important advantage stems from the fact that a pure sinusoidal reference signal 472 is not required for operation. In fact, the combination of the class D amplifier 460 and the resonant circuit 480 can use reference wave signals of various waveform shapes. Constant waveform shapes, such as square waves, can often be generated with higher fidelity than pure sinusoidal waveforms. As a result, the combination of the class D amplifier 460 and the resonant circuit 480 enables operation with a highly stable reference wave signal.

  Returning to FIG. 4A, high voltage RF signal 482 may be monitored by signal monitor 490, which may be optional and may or may not be provided to voltage source 106. Signal monitor 490 receives feedback signal 484 from resonant circuit 480, which is generally a low amplitude replica of high voltage RF signal 482. Although the feedback signal 484 is typically much smaller in amplitude than the high voltage RF signal 482, the amplitude of the feedback signal 484 is generally proportional in all respects to the amplitude of the high voltage RF signal 482.

  The feedback signal received from the resonant circuit by signal monitor 490 can be sent as control signal 492 to PID control loop 420 and / or reference wave generator 470. Based on modulated signal 492, PID control loop 420 can send modified control signals 422 and 422 to switch mode power supply 430 and linear regulator 450, respectively, to optimize the waveform and amplitude of high voltage RF signal 482. For example, PID control loop 420 can modify the envelope of modified voltage signal 432 based on control signal 492 to maximize the amplitude of high voltage RF signal 482.

  In some embodiments, the resonant frequency of resonant circuit 480 may not perfectly match the frequency of reference wave signal 472. For example, this may be due to an incorrect value of the inductance of inductor 486 and / or the capacitance of capacitor 488. In addition, the inductance of inductor 486 and / or the capacitance of capacitor 488 may change over time. This may occur, for example, because the class D amplifier 460 distorts the output frequency of the RF signal 462 and the frequency of the RF signal 462 does not match the reference signal wave 472. This mismatch may reduce the efficiency of the power supply 106 as the resonant circuit 480 is not an effective resonator for the RF signal 462.

  Several techniques can be implemented to compensate for this discrepancy. In some embodiments, the frequency of reference wave signal 472 can be scanned by reference wave generator 470 while monitoring control signal 492 simultaneously. The reference wave generator 470 can select the optimum frequency of the reference wave signal 472 as the frequency that maximizes the amplitude of the control signal 492.

  In some embodiments, the capacitance of capacitor 488 can be varied in resonant circuit 480 to identify which capacitance value maximizes the amplitude of control signal 492. For this purpose, capacitor 488 may be a variable capacitor.

  The above-described techniques for compensating for frequency mismatch may be implemented directly in hardware, in software, or both. For example, controller 108 can be configured to perform one or more of these methods to compensate for frequency mismatches. The controller 108 can be configured to perform these methods continuously and / or continuously to optimize frequency agreement automatically. Alternatively, the controller 108 can be configured to perform these methods only when instructed by the user, for example, when the user activates the control means of the user interface 112. The techniques for compensating for the frequency mismatch disclosed herein are typically completed within 5 minutes (eg, within 3 minutes, 2 minutes, 1 minute) when executed by the controller 108 Do.

  A high voltage RF signal 482 is applied to the ion trap 104 (eg, to the central electrode 302 of the ion trap 104) to selectively expel trapped ions for detection by the detector 118. The range of mass to charge ratios that can be analyzed using the ion trap 104 depends on the profile of the RF signal 462 (e.g., envelope and maximum amplitude) in addition to other factors. By varying these characteristics of the RF signal 482, the voltage source 106 can select (under the control of the controller 108) a range of mass to charge ratios to be analyzed.

  In some embodiments, voltage source 106 can include multiple reference wave generators 470 and / or multiple resonant circuits 480. In operation, the combination of the particular reference wave generator 470 and the particular resonant circuit 480 is a controller to generate a high voltage RF signal 482 suitable for analysis of a particular range of mass to charge ratio using the ion trap 104. 108 can be selected. To change the range of mass to charge ratios to analyze, the controller 108 selects a different reference generator 470 and / or a resonant circuit 480.

V. Detector Detector 118 is configured to detect charged particles exiting ion trap 104. These charged particles may be positive ions, negative ions, electrons, or a combination thereof.

  A wide variety of different detectors can be used in the analyzer 100. FIG. 5A shows one embodiment of a detector 118 that includes a Faraday cup 500. The Faraday cup 500 comprises a circular base 502 and a cylindrical side wall 504. In general, the shape and dimensions of the Faraday cup 500 can be varied to optimize the sensitivity and resolution of the analyzer 100.

  For example, the base 502 can comprise various cross-sectional shapes, including square, rectangular, oval, circular, or any other regular or irregular shape. Base 502 may, for example, be flat or curved.

  FIG. 5B shows a side view of the Faraday cup 500. In some embodiments, the length 506 of the sidewall 504 is less than or equal to 20 mm (eg, less than or equal to 10 mm, less than or equal to 5 mm, less than or equal to 2 mm, less than or equal to 1 mm, or even 0 mm). In general, the length 506 can be selected according to various criteria including maintaining the compactness of the analyzer 100, providing the necessary selectivity when detecting charged particles, and the degree of resolution. In some embodiments, sidewalls 504 conform to the cross-sectional shape of base 502. However, more generally, the sidewalls 504 need not conform to the shape of the base 502 and can have various cross-sectional shapes that are different than the shape of the base 502. Furthermore, the sidewall 504 need not be cylindrical. In some embodiments, for example, the side wall 504 may be curved along the axial direction of the Faraday cup 500.

  In general, the Faraday cup 500 may be relatively small. The largest dimension of the Faraday cup 500 corresponds to the largest linear distance between any two points of the cup. In some embodiments, for example, the largest dimension of the Faraday cup 500 is 30 mm or less (eg, 20 mm or less, 10 mm or less, 5 mm or less, 3 mm or less).

  Typically, the thickness of base 502 and / or the thickness of sidewalls 504 are selected to ensure efficient detection of charged particles. In some embodiments, the thickness of base 502 and / or sidewall 504 is 5 mm or less (eg, 3 mm or less, 2 mm or less, 1 mm or less).

  The side wall 504 and base 502 of the Faraday cup 500 are generally made of one or more metals. Metals that can be used to make the Faraday cup 500 include, for example, copper, aluminum, and silver. In some embodiments, the Faraday cup 500 includes one or more cover layers on the surface of the base 502 and / or the side wall 504. Such coating layer or layers can be made of materials such as copper, aluminum, silver and gold.

  During operation of the analyzer 100, when charged particles are ejected from the ion trap 104, these charged particles can drift or accelerate into the Faraday cup 500. Once in the Faraday cup 500, charged particles are trapped on the surface of the Faraday cup 500 (the surface of the base 502 and / or the sidewall 504). Charged particles trapped on either the base 502 or the sidewall 504 generate a current that is measured (eg, by an electrical circuit in the detector 118) and reported to the controller 108. If these charged particles are ions, then the measured current is an ion current, the amplitude of which is proportional to the abundance of the measured current ions.

  The amplitude of the potential applied to the central electrode 302 of the ion trap 104 is changed (eg, variable amplitude signal, high voltage RF signal 482 is applied) to obtain a mass spectrum of the analyte, and Selectively eject ions of mass to charge ratio. For each change in amplitude corresponding to a different mass to charge ratio, the ion current corresponding to the ejected ion of the selected mass to charge ratio is measured using the faraday cup 500. The measured ion current as a function of the potential applied to the electrode 302 corresponds to the mass spectrum and is reported to the controller 108. In some embodiments, controller 108 converts the applied voltage to a particular mass to charge ratio based on the algorithm and / or calibration information of ion trap 104.

  Following ejection from the ion trap 104 via the end cap electrode 306, the charged particles can be accelerated to strike the detector 118 by forming an electric field between the detector 118 and the end cap electrode 306. In some embodiments, where the detector 118 includes, for example, a Faraday cup 500, the conductive surface of the Faraday cup 500 is maintained at the ground potential established by the power supply 106 and a positive potential is applied to the end cap electrode 306 Be done. These applied potentials cause positive ions to be repelled from the end cap electrode 306 towards the grounded conductive surface of the Faraday cup 500. In addition, electrons passing through the end cap electrode 306 are attracted to the end cap electrode 306 and thus do not collide with the Faraday cup 500. Thus, this arrangement improves the signal to noise ratio. More generally, in this configuration, as long as the Faraday cup 500 is at a lower potential than the end cap electrode 306, it may be at any potential other than ground.

  In some embodiments, it is desirable to detect negatively charged particles (eg, negative ions and / or electrons). To detect such particles, the Faraday cup 500 is biased to a higher voltage than the end cap electrode 306 to attract negatively charged particles to the Faraday cup 500.

  In some embodiments, detector 118 can include a Faraday cup 500 with two regions separated by an insulating region. Different bias potentials can be applied to each region. For example, FIG. 5C shows a faraday cup 500 including two conductive regions 510 and 520 separated by an insulating region 530. By grounding end cap electrode 306 and applying positive and negative bias voltages to regions 510 and 520, region 510 can detect negatively charged particles, and region 520 can detect positively charged particles. This configuration can simultaneously detect positively charged ions and negatively charged ions, and can provide additional information when measuring a mass spectrum. Alternatively, the measurement of positively charged ions and negatively charged ions can be performed by first activating either of the regions 510 and 520 by applying a bias potential and then activating the other region. It can be done in order. Alternatively, in some embodiments, detector 118 can include two Faraday cups 500, where different bias voltages are used to measure positively charged ions and negatively charged ions. The voltage is applied to each Faraday cup 500.

  In some embodiments, detector 118 may be fixed directly to housing 122. For example, FIG. 5C shows that housing 122 includes one or more electrodes 550 and 552 in contact with Faraday cup 500. Alternatively, in some embodiments, one or more electrodes 550 and 552 may be attached directly to the Faraday cup 500. In some embodiments, one electrode can be used to bias the Faraday cup 500 and another electrode can be used to measure the current generated by the faraday cup 500. Alternatively, in some embodiments, the application of the bias voltage and the current measurement can be performed using the same electrode.

  In some embodiments, the housing 122 can be configured to allow the detector 118 to be easily attached and detached. For example, as shown in FIG. 5C, the housing 122 includes an opening through which the Faraday cup 500 can be secured and held by the holding element 540 (eg, a screw or other fastener). This is particularly advantageous when the Faraday cup 500 is broken or contaminated, which can be determined by detecting phantom peaks during mass spectral measurements as described above. The contaminated Faraday cup 500 can be replaced by removing the cup 500 from the opening of the housing 122 and attaching a replacement. The contaminated Faraday cup can be repaired or cleaned in situ. For example, the Faraday cup 500 can be baked in a portable furnace so that the sticky particles on the surface of the Faraday cup 500 are vaporized. The cleaned Faraday cup may be reinserted into the housing 122. This replaceability minimizes analyzer down time even if some components of the analyzer 100 are contaminated. In some embodiments, the contaminated Faraday cup 500 can be cleaned by heating while attached to the housing 122 (eg, applying a large current to the base 502 and the sidewall 504). Contamination particles released from the surface of base 502 and / or sidewall 504 may be removed from the analyzer by pressure regulation subsystem 120.

  In some embodiments, as described in Section I, the Faraday cup 500 is implemented as a component of the pluggable and replaceable module 148. In this modular configuration, the Faraday cup 500 can be formed, for example, as a recess in the plate of conductive material. This plate is attached directly to another component of the module 148 such as the ion trap 104, the opening of the end cap electrode 306 is aligned with this recess, and the ions ejected from the ion trap 104 directly enter the Faraday cup You may do so. Different types of analytes can be selectively detected using modules with different Faraday cup sizes.

  FIG. 5D shows a detector 118 that includes an array of Faraday cup detectors 500, which may or may not be integrally formed. An array of detectors may be advantageous, for example, if the ion trap 104 comprises an array of ion chambers 330. The end cap electrode 306 can include a plurality of apertures 560 aligned with each ion chamber, with ions ejected from each chamber passing substantially only one of the apertures 560. After passing through one of the apertures 560, the ions are incident on any of the Faraday cup detectors 500 of the array. This array-based approach to ion ejection and detection significantly improves the efficiency with which the ejected ions are detected. In the geometry of the array shown in FIG. 5D, the size of each Faraday cup 500 can be adapted to the size of each aperture 560 formed in the end cap electrode 306.

  In some embodiments, a biased repulsive grid or magnetic field can be placed in front of the Faraday cup 500 to prevent secondary charged particle emissions that can distort the measurement of the ejected ions from the ion trap 104. Alternatively, in some embodiments, secondary electron emission from the Faraday cup 500 can be used for detection of emitted ions.

  Although the above description has focused on low power operation and compact size Faraday cup detectors, a variety of other detectors can be used with the analyzer 100 in more general terms. For example, other suitable detectors include electron multipliers, photomultipliers, scintillation detectors, image current detectors, daily detectors, phosphor-based detectors, and incidents. Included are other detectors where charged particles generate photons, which are detected (ie, detectors that utilize charge-photon energy conversion mechanisms).

VI. Pressure Regulation Subsystem The pressure regulation subsystem 120 is generally configured to regulate the gas pressure in the gas path 128, including the internal volume of the ion source 102, the ion trap 104, and the detector 118. As described above in Section I, during operation of the analyzer 100, the pressure regulation subsystem 120 can provide a gas pressure in the analyzer 100 of at least 100 mTorr (eg, at least 200 mTorr, at least 500 mTorr, at least 700 mTorr, 1 Maintain at or above Torr, 2 Torr or above, 5 Torr or above, 10 Torr or more and / or 100 Torr or less (eg 80 Torr or less, 60 Torr or less, 50 Torr or less, 40 Torr or less, 30 Torr or less, 20 Torr or less) .

  In some embodiments, pressure regulation subsystem 120 maintains the gas pressure in some components of analyzer 100 in the above range. For example, pressure regulation subsystem 120 may provide a gas pressure of ion source 102 and / or ion trap 104 and / or detector 118 between 100 mTorr and 100 Torr (e.g., between 100 mTorr and 10 Torr, 200 mTorr Maintain at 500 torr, 500 mTorr, 50 torr, 500 mTorr and 100 torr). In some embodiments, the gas pressure of at least two of the ion source 102, the ion trap 104, and the detector 118 is the same. In some embodiments, the gas pressure of all three components is the same.

  In some embodiments, the gas pressure of at least two of the ion source 102, the ion trap 104, and the detector 118 differ by relatively small amounts. For example, the pressure regulation subsystem 120 may have a difference in pressure of at least two of the ion source 102, the ion trap 104, and the detector 118 by less than or equal to 100 mTorr (e.g., less than 50 mTorr, less than 40 mTorr, less than 30 mTorr, 20 millitorr or less, 10 millitorr or less, 5 millitorr or less, 1 millitorr or less). In some embodiments, the gas pressure difference between all of the ion source 102, the ion trap 104, and the detector 118 is less than or equal to 100 mTorr (e.g., less than 50 mTorr, less than 40 mTorr, less than 30 mTorr, less than 20 mTorr, 10 mTorr or less, 5 mTorr or less, 1 mTorr or less).

  As shown in FIG. 6A, pressure regulation subsystem 120 can include a scroll pump 600 with a pump container 606 with one or more interleaved scroll flanges 602 and 604. The relative orbital motion between the scroll flanges 602 and 604 captures gas and liquid and guides the pumping action. In some embodiments, the scroll flange 604 can be fixed while the scroll flange 602 orbits an eccentric track with or without rotation. In some embodiments, both scroll flanges 602 and 604 move about a biased center of rotation. FIG. 6B shows a schematic view of the scroll flange 602. Examples of scroll flange geometries include, but are not limited to, stretch lines, Archimedean spirals, and hybrid curves.

  The orbital motion of the crawl flanges 602 and 604 causes the scroll pump 600 to generate very low amplitude vibrations and low noise during operation. Thus, the scroll pump 600 can be connected directly to the ion trap 104 with substantially no adverse effects during mass spectrometry. Orbital scroll flange 602 can be equilibrated with a simple mass to further reduce oscillatory coupling. Since the scroll pump 600 has few moving parts and generates very small amplitude vibrations, the reliability of such pumps is generally very high.

  Scroll pump 600 is typically compact in size and small in mass. In some embodiments, for example, the largest dimension of the scroll pump 600 (eg, the maximum linear distance between any two points on the scroll pump 600) is less than 10 cm (eg, less than 8 cm, less than 6 cm, 5 cm) Less than 4 cm, less than 3 cm, less than 2 cm). In some embodiments, the scroll pump 600 weighs less than 1.0 kg (e.g., less than 0.8 kg, less than 0.7 kg, less than 0.6 kg, less than 0.5 kg, less than 0.4 kg, less than 0.3 kg, less than 0.2 kg) is there.

  Because of the small size and light weight of the scroll pump 600, the scroll pump can be incorporated into the analyzer 100 in a variety of configurations. In some embodiments, for example, as shown in FIGS. 1D and 1E, scroll pump 600 (as part of pressure regulation subsystem 120) may be attached directly to support base 140 (eg, printed circuit board) is there. In some embodiments, scroll pump 600 (as part of pressure regulation subsystem 120) may be implemented as a component of pluggable and replaceable module 148 and further including ion source 102, ion trap 104, and / or Or can be attached directly to one or more other components of module 148, such as detector 118.

  FIG. 6A shows scroll pump 600 attached directly to printed circuit board 608. The pump inlet 610 is directly connected to the pump inlet 620 of the manifold 121. The scroll pump 600 can be directly fixed to the substrate 608 by the fixing element 630 and the fixing element 632, which can be positioned at 1 cm or more (eg, 2 cm or more, 3 cm or more, 4 cm or more) from the pump inlets 610 and 620 Thus, the oscillatory coupling between the pump 600 and the substrate 608 is reduced. Alternatively, rather than a direct connection between the pump 600 and the substrate 608, in some embodiments, the pump inlet 610 and the pump inlet 620 may be connected by a tube (a flexible or rigid tube) .

  Scroll pumps suitable for use in the pressure adjustment subsystem 120 are commercially available, for example, from Agilent Technologies (Santa Clara, CA). In addition to a scroll pump, other pumps may be used with pressure regulation subsystem 120. Examples of suitable pumps include membrane pumps, membrane pumps, and roots blower pumps.

  The use of a small, single mechanical pump offers several advantages over the pumping mechanism employed in conventional mass spectrometers. In particular, conventional mass spectrometers typically use a large number of pumps, at least one of which operates at high rotational speeds. Large mechanical pumps operating at high rotational speeds generate mechanical vibrations that can be coupled to the other components of the analyzer, resulting in unwanted noise in the measurement information. Furthermore, even if steps have been taken to isolate components from such vibrations, the isolation mechanism typically increases the size of the analyzer, which can sometimes be greatly increased. Furthermore, a large pump operating at high speed consumes a large amount of power. Thus, conventional mass spectrometry involves large power supplies to meet these requirements, further increasing the size of such instruments.

  In contrast, a single mechanical pump, such as a scroll pump, can be used with the analyzers disclosed herein to control the gas pressure in each component of the system. By operating this mechanical pump at a relatively low rotational speed, the mechanical coupling of the vibrations to the other components of the analyzer is greatly reduced or eliminated. Furthermore, by operating at low rpm, the amount of power consumed by the pump is also small enough that the low requirement can be satisfied by the voltage source 106.

  In some embodiments, the single mechanical pump is operated at less than 6000 cycles per minute (eg, less than 5000 cycles per minute, less than 4000 cycles per minute, less than 3000 cycles per minute, less than 2000 cycles per minute) By doing this, the pump can maintain the desired gas pressure inside the analyzer 100 while at the same time its power consumption requirements can be met by the voltage source 106.

VII. Housing As described above in Section I, mass spectrometer 100 includes a housing 122 that encloses the components of the spectrometer. FIG. 7A shows a schematic view of one embodiment of the housing 122. The sample inlet 124 is integrated within the housing 122 and is configured to introduce gas particles into the gas path 128. Display 116 and user interface 112 are also integrated into housing 122.

  In some embodiments, display 116 is an active or passive liquid crystal or light emitting diode (LED) display. In some embodiments, display 116 is a touch screen display. A controller 108 is connected to the display 116 and can display various information to the user of the mass spectrometer 100 using the display 116. The displayed information can include, for example, information on the identity of one or more substances scanned by the analyzer 100. This information can also include mass spectrometry (eg, measurement of the abundance of ions detected by detector 118 as a function of mass to charge ratio). Furthermore, the information to be displayed may be operating parameters and information related to the mass spectrometer 100 (e.g. measured ion current, voltages applied to various components of the mass spectrometer 100, current modules attached to the spectrometer 100) The name and / or identifier associated with 148, the alert associated with the substance identified by the analyzer 100, and the configured user preferences for the operation of the analyzer 100 can be included. Information such as configured user preferences and operational settings may be stored in storage 114 and retrieved by controller 108 for display.

  In some embodiments, as shown in FIG. 7A, the user interface 112 includes a series of control means incorporated into the housing 122. These control means are operable by the user of the analyzer 100 and may include buttons, sliders, rockers, switches, and other similar control means. By operating the control means of the user interface 112, the user of the analyzer 100 can activate various functions. For example, in some embodiments, actuation of any of these control means initiates a scan by the analyzer 100, during which time the analyzer draws a sample (eg, gas particles) into the sample inlet 124, Ions are generated from the particles and further trapped and analyzed using ion trap 104 and detector 118. In some embodiments, when any control means is activated, the analyzer 100 is reset prior to performing a new operation. In some embodiments, the analyzer 100 may be activated by a user (e.g., after replacing any of the analyzer 100 components such as the module 148 and / or the filter connected to the sample inlet 124) ) Control means for restarting the analyzer 100.

  If the display 116 is a touch screen display, even some or all of the user interface 112 can be implemented as a series of touch screen controls on the display 116. That is, some or all of the control means of the user interface 112 may be touch sensitive areas of the display 116 that can be actuated by the user by touching the display 116 with a finger.

  As described above in Section I, in some embodiments, the mass spectrometer 100 includes a replaceable and pluggable module 148 that includes an ion source 102, an ion trap 104, and (optionally) a detector 118. be able to. If the mass spectrometer 100 includes a pluggable module 148, the housing 122 can include an opening that allows a user to access the interior of the housing 122 and replace the module 148 without disassembling the housing 122. FIG. 7B is a cross-sectional view of mass spectrometer 100 including pluggable module 148. In FIG. 7B, the housing 122 includes an opening 702 and a partition 704 that closes the opening 702. When replacing module 148, a user of analyzer 100 can open divider 704 to expose the interior of analyzer 100. The partition 704 is arranged to allow direct access to the pluggable module 148 so that the user can remove the module 148 from the support base 140 and replace it with another one without disassembling the housing 122 . Then, the user can close the opening 702 again by fixing the partition 704.

  In FIG. 7B, the divider 704 is realized in the form of a retractable door. However, more generally, various partitions can be used to close the opening of the housing 122. For example, in some embodiments, partition 704 may be implemented as a lid that is completely removable from housing 122.

  In general, mass spectrometer 100 can include a variety of different sample inlets 124. For example, in some embodiments, the sample inlet 124 includes an aperture configured to draw gas particles directly from the ambient environment of the analyzer 100 into the gas path 128. The sample inlet 124 can include one or more filters 706. For example, in some embodiments, filter 706 is a HEPA filter to prevent dust and other solid particles from entering analyzer 100. In some embodiments, the filter 706 comprises a molecular sieve material that captures water molecules.

  As mentioned above, conventional mass spectrometry operates at low internal gas pressure. In order to maintain low gas pressure, conventional mass spectrometers include one or more filters attached to the sample inlet. These filters are selective and filter certain types of materials, such as atmospheric gas particles (eg, nitrogen and / or molecular oxygen) to prevent them from entering the mass spectrometer. These filters may be particularly adapted for certain types of analytes, such as biological molecules, and other types of molecules can be filtered out. As a result, the filters used in conventional mass spectrometers can include pinch valves and thin film filters made of materials such as polydimethylsiloxane that allow selective transfer of material, and can be used to The stream is filtered to remove certain types of particles from the stream. Without such a filter, conventional mass spectrometers would not function but they could not maintain low gas pressure and some of the particles introduced into this mass spectrometer would interfere with the operation of some components That's why. As an example, thermionic sources used in conventional mass spectrometers do not operate in the presence of more or less concentrated atmospheric oxygen.

  There are several disadvantages to using filters for specific substances in conventional mass spectrometers. For example, because these filters are selective, only a small number of analytes can be analyzed without changing the filters and / or operating conditions, which can be cumbersome. In particular, for users who are not skilled in mass spectrometers, it may be difficult to reconfigure the analyzer for a particular analyte by choosing an appropriate selective filter. Furthermore, the filters used in conventional mass spectrometers cause a time delay since the analyte particles do not diffuse instantaneously through the filter. Depending on the selectivity of the filter and the concentration of the analyte, a considerable delay occurs between the time when the analyte first contacts and the time when a sufficient amount of analyte ions are detected to generate mass spectral information There is.

  However, because the mass spectrometers disclosed herein operate at higher pressures, it is not necessary to maintain low gas pressure in the analyzer, including filters such as thin film filters. Operating without filters of the type used in conventional mass spectrometers, the analyzers disclosed herein can analyze a larger number of different types of samples without significant reassembly and analyze faster Can do Furthermore, the components of the analyzer disclosed herein are generally less sensitive to atmospheric gases such as nitrogen and oxygen, and these gases can be introduced into the analyzer with the analyte particles of interest, which increases the speed of analysis And improve the operating requirements of other components of the analyzer (e.g., the pumping load of pressure regulation subsystem 120).

  Thus, in general, the filter (eg, filter 706) used in the analyzer disclosed herein does not filter atmospheric gas particles (eg, nitrogen and oxygen molecules) from the stream of gas particles entering sample inlet 124. . In particular, the filter 706 passes at least 95% or more of the atmospheric gas particles contacting the filter.

  Different types of filters 706 are replaceable and can be replaced by the user of the analyzer 100 if it becomes dirty or less effective. In some embodiments, the mass spectrometer 100 can include multiple filters 706, and the user can selectively attach any one or more of these filters, depending on the nature of the sample being analyzed it can.

  In some embodiments, the sample inlet 124 can be configured to receive the substance to be analyzed by direct injection. For example, filter 706 may be replaced with a sample injection port attached to sample inlet 124. When using the analyzer 100, substances injected into the sample inlet 124 through the sample injection port are introduced into the gas path 128, ionized by the ion source 102, and analyzed by the ion trap 104 and the detector 118. .

  In some embodiments, the analyzer 100 can include various sample introduction modules that can be attached to the housing 122 to introduce different types of analytes into the analyzer 100. The sample introduction module 750 is schematically illustrated in FIG. 7C. Module 750 is attached to housing 122 such that electrodes 752 in housing 122 establish electrical connection with corresponding electrodes in module 750. The electrodes 752 are connected to the controller 108 and the voltage source 106 on the support base 140. The voltage source 106 can supply power to the module 750 via the electrodes 752, and transmit and receive signals to and from the controller 108 and the module 750. When module 750 is attached to housing 122 (e.g., using a screw or keyed connection, a magnetic attachment mechanism, or any of a variety of other attachment mechanisms), voltage source 106 automatically supplies power. Module 750 is activated. Once activated, the module 750 reports its identity to the controller 108, which can display information on the activated module on the display 116. The controller 108 can receive configuration settings and other operating parameters from the storage device 114 so that the analyzer 100 is automatically configured to analyze the sample introduced via the module 750.

  In general, various sample introduction modules can be used with the analyzer 100. For example, in some embodiments, module 750 is a steam thermal desorption module. In some embodiments, module 750 is a low temperature plasma module. In some embodiments, module 750 is an electrospray ionization module. Each of these modules can be used interchangeably with the analyzer 100 to analyze a wide variety of different samples.

  In addition to the replaceable module 750, the analyzer 100 can include various sensors. For example, in some embodiments, mass spectrometer 100 can include limit sensor 708 coupled to controller 108. The limit sensor 708 detects gas particles in the ambient environment of the mass spectrometer and reports the gas concentration to the controller 108. During operation of the mass spectrometer 100 by the user, the controller 108 monitors the duration and concentration of the gas measured by the limit sensor 708 and alerts if the user's exposure to gas particles exceeds a threshold concentration or threshold time limit. Are displayed to the user (eg, via the display device 116). Information regarding threshold exposure concentrations and time limits may be stored in storage 114 and may be retrieved, for example, by controller 108. Exemplary limit sensors that may be used with mass spectrometer 100 include flammable / low explosion level gas sensors, photoionization sensors, electrochemical sensors, and temperature and humidity sensors.

  In some embodiments, mass spectrometer 100 can include an explosion hazard sensor 710. An explosion hazard sensor 710 is connected to the controller 108 to detect the presence of detonation material in the vicinity of the analyzer 100. The threshold concentrations of various detonation materials are stored in storage 114 and can be retrieved by controller 108. During operation of the analyzer 100, the controller 108 may display a warning message to the user of the analyzer 100 via the display 116 if the concentration of one or more deflagrations measured by the sensor 710 exceeds a threshold. . In some embodiments, the warning message may prompt the user to discontinue use of the analyzer 100 or within an auxiliary shield (eg, a cage) to prevent ignition of the one or more detonation materials. I can advise you to use it. Explosive hazard sensors that can be used with mass spectrometer 100 include, for example, combustible sensors available from MSA (Canterbury Township, PA) and RAE Systems (San Jose, CA).

The housing 122 is generally shaped to allow the user to comfortably operate with one or both hands. In general, housing 122 can have a wide variety of different shapes. However, the choice and integration of the components of the analyzer 100 disclosed herein generally make the housing compact. As shown in FIGS. 7A and 7B, regardless of overall shape, housing 122 is provided with a maximum dimension a ₁ which corresponds to the longest straight line distance between any two points on the outer surface of the housing. In some embodiments, a ₁ is 35 cm or less (eg, 30 cm or less, 25 cm or less, 20 cm or less, 15 cm or less, 10 cm or less, 8 cm or less, 6 cm or less, 4 cm or less) .

  Furthermore, due to the choice of components in the analyzer 100, the overall weight of the analyzer 100 is significantly lower than conventional mass spectrometers. In some embodiments, the overall weight of the analyzer 100 is 4.5 kg or less (e.g., 4.0 kg or less, 3.0 kg or less, 2.0 kg or less, 1.5 kg or less, 1.0 kg or less, 0.5 kg or less).

VIII. Modes of Operation In general, mass spectrometer 100 operates according to a variety of different modes of operation. FIG. 8A shows a general series of steps performed in different operating modes for scanning and analyzing a sample. In a first step 802, a scan of the sample is started. In some embodiments, this scan is initiated by the user of the analyzer 100. For example, the analyzer 100 can be configured to operate in a "one touch" mode where the user can initiate scanning of the sample simply by activating the control means of the user interface 112. FIG. 8B shows an embodiment of the analyzer 100 that includes control means 820 for the user interface 112 to initiate a scan. When the control means 820 is actuated by the user, a scan of the sample (shown as gas particles 822 in FIG. 8B) is initiated.

  In some embodiments, the controller 108 can automatically initiate a scan based on one or more sensor readings. For example, if the analyzer 100 includes limit sensors, such as photo ionization detectors and / or LEL sensors, the controller 108 can monitor the signals from these sensors. For example, if these sensors indicate that a potential substance of interest has been detected, the controller 108 can initiate a scan. In general, controller 108 can use events or conditions based on a wide variety of different sensors to automatically initiate a scan.

  In some embodiments, the analyzer 100 can be configured to run in a "continuous scan" mode. When the analyzer 100 is placed in the continuous scan mode, the scan is repeatedly started every fixed interval. This time interval may be configurable by the user, and the value of the time interval may be stored in storage 114 and retrieved by controller 108. Thus, in step 802 of FIG. 8A, when the analyzer 100 is in continuous scan mode, a scan is initiated by the analyzer.

  After this scan is initiated, the sample is introduced into the analyzer 100 at step 804. The sample can be introduced into the analyzer using a variety of different methods. In some embodiments, if the sample comprises gas particles (eg, gas particles 822 in FIG. 8B), controller 108 actuates valve 129 to open the valve and allow gas particles to flow into analyzer 100 (eg, In the gas path 128). If the sample inlet 124 includes a filter 706, the gas particles pass through the filter, which removes dust and other solid matter from the stream of gas particles. As mentioned above, the pressure regulation subsystem maintains a gas pressure below atmospheric pressure in the gas path 128. As a result, when the valve 129 opens, gas particles 822 are drawn into the sample inlet 124 by the differential pressure between the gas path 128 and the environment surrounding the analyzer 100. Alternatively or additionally, pressure regulation subsystem 120 may allow gas particles to flow into analyzer 100.

  In some embodiments, the sample can be introduced into the analyzer 100 by direct injection. As described above in Section VII, the analyzer 100 can include a sample injection port connected to the sample inlet 124. The sample injection port allows the user of the analyzer 100 to inject the sample directly into the sample inlet 124 for analysis. Once injected, the sample enters gas path 128.

  In some embodiments, the partially ionized sample can be drawn into the analyzer 100 by electrostatic or current forces. For example, charged particles can be accelerated into the analyzer 100 (eg, via the sample inlet 124) by applying an appropriate potential to the electrodes of the analyzer 100.

  Subsequently, at step 806, the sample is ionized in the ion source 102. As noted above, the sample inlet 124 can be positioned at different locations along the gas path 128 relative to other components of the analyzer 100. For example, in some embodiments, the sample inlet 124 can be arranged such that gas particles introduced into the analyzer 100 first enter the ion trap 104 from the sample inlet 124. For example, in some embodiments, the sample inlet 124 can be arranged such that gas particles introduced into the analyzer 100 first enter the ion source 102 from the sample inlet 124. In some embodiments, the sample inlet 124 can be arranged such that gas particles enter the detector 118 first from the sample inlet 124. Further, the sample inlet 124 can be arranged such that gas particles entering the analyzer 100 enter the gas path 128 from a point between the ion source 102 and / or the ion trap 104 and / or the detector 118.

  After the sample (eg, as gas particles 822) is introduced into the analyzer 100 at a point along the gas path 128, some of the gas particles enter the ion source 102. If the sample inlet 124 is not arranged such that the gas particles 822 enter the ion source 102 directly, the migration of the gas particles 822 into the ion source 102 occurs by diffusion. Once in the ion source 102, the controller 108 activates the ion source 102 to ionize the gas particles, as disclosed in Section II.

  Next, the ions generated in step 806 are trapped in the ion trap 104 in step 808. As discussed above in Section II, migration of ions from ion source 102 to ion trap 104 generally occurs under the influence of an electric field generated between ion source 102 and ion trap 104. Once in the ion trap 104, ions are trapped by the electric field inside the trap and circulate within the aperture of the central electrode 302 and between the end cap electrodes 304 and 306. The electric field within the ion trap 104 is generated by the voltage source 106 under the control of the controller 108, which applies an appropriate potential to the electrodes 302, 304 and 306 to generate a trapped electric field.

  At step 810, trapped and circulating ions in the ion trap 104 are selectively evacuated from the trap. As described above in Section III, selective ejection of ions from the trap 104 is under the control of the controller 108, which controls the signal to change the amplitude of the RF voltage applied to the central electrode 302. Transmit to voltage source 106. When the amplitude of this potential changes, the amplitude of the electric field of the internal aperture of the center electrode 302 also changes. Furthermore, as the amplitude of the electric field in the central electrode 302 changes, circulating ions with a specific mass-to-charge ratio fall out of the trajectory in the central electrode 302 and ion trap through one or more apertures of the end cap electrode 306 It is discharged from 104. The controller 108 sweeps the amplitude of the applied potential according to a defined function (e.g., a linear amplitude sweep) to selectively eject ions of a particular mass to charge ratio from the ion trap 104 into the detector 118. Configured The rate at which the applied voltage is swept can be determined automatically by controller 108 (eg, to achieve the target resolution of analyzer 100) and / or can be set by the user of analyzer 100.

  As these ions are selectively ejected from the ion trap 104, they are detected by the detector 118 at step 812. As disclosed in Section V, a wide variety of different detectors can be used to detect these ions. For example, in some embodiments, detector 118 includes a Faraday cup that is used to detect these ejected ions.

  For each mass-to-charge ratio selected by the amplitude of the charge applied to central electrode 302 in ion trap 104, detector 118 measures the current associated with the abundance of ions detected at the selected mass-to-charge ratio. Do. The measured current is sent to the controller 108. As a result, the information that controller 108 receives from detector 118 corresponds to the abundance of ions detected as a function of the mass to charge ratio of these ions. This information corresponds to the mass spectrum of the sample.

  More generally, the controller 108 is configured to detect the ions according to the mass to charge ratio of the ions, which causes the controller 108 to detect or receive a signal correlated to the detection of the ions and related to the mass to charge ratio of the ions. It means to do. In some embodiments, the controller 108 detects or receives information about ions as a direct function of mass to charge ratio. In some embodiments, controller 108 receives information regarding the ion as a function of another quantity related to the mass to charge ratio of the ion, such as the potential applied to ion trap 104, for example. In all these embodiments, controller 108 detects ions according to mass to charge ratio.

  At step 814, the information received from detector 118 is analyzed by controller 108. Generally, to analyze this information, controller 108 (e.g., electronic processor 110 in controller 108) compares the mass spectrum of the sample to the reference information to determine if the mass spectrum of the sample indicates any known material. To judge. This reference information may, for example, be stored in storage 114 and retrieved by controller 108 for analysis. In some embodiments, controller 108 may retrieve reference information from a database stored at a remote location. For example, for use in analyzing information measured by the detector 118, the controller 108 can communicate with such a database using the communication interface 117 to obtain a mass spectrum of a known substance.

  The information measured by detector 118 is analyzed by controller 108 to determine information about the identity of the sample. If the sample contains a large number of compounds, the controller 108 can compare the measurement information from the detector 118 with the reference information to determine information on the identification of some or all of the large number of substances.

  The controller 108 is configured to seek various information regarding the identity of one sample. For example, in some embodiments, this information includes one or more of a sample's common name, IUPAC name, CAS number, UN number, and / or its chemical formula. In some embodiments, the information regarding the identity of the sample is whether the sample belongs to a particular type of substance (eg, explosives, high energy substances, fuels, oxidants, strong acids or bases, poisons) Contains information. In some embodiments, this information may include information related to hazards associated with the sample, handling instructions, safety alerts, and reporting instructions. In some embodiments, this information can include information regarding the concentration or level of the sample measured by the analyzer.

  In some embodiments, this information can include an indication of whether the sample matches the target material. For example, when a scan is initiated at step 802, a user of the analyzer 100 can place the analyzer in the target mode, in which case the analyzer 100 scans the sample, in particular a series of samples being identified. Determine if it matches any of the target substances. The controller 108 can search for specific spectral features in the measured mass spectral information using various data analysis techniques such as digital filtering and expert systems. For a particular target substance, the controller 108 can look for mass spectral features that are characteristic of the target substance, such as peaks at a particular mass-to-charge ratio. If a particular spectral feature is missing from the measured mass spectral information, or if the measured information includes a spectral feature that should not appear, then information regarding the identity of the sample identified by the controller 108 indicates that the sample is the target material. May contain an indication that they do not match. The controller 108 can be configured to identify such information for a number of target substances.

  After sample analysis is complete, controller 108 displays information about the sample at step 816 using the display 116 to the user. The displayed information varies depending on the operation mode of the analyzer 100 and the operation of the user. As disclosed in Section I, the analyzer 100 is configured for use by an untrained person in interpreting mass spectra. For those untrained, complete mass spectra (eg, ion abundance as a function of mass-to-charge ratio) are often poorly understood. As a result, the analyzer 100 is configured at step 816 not to display the measured mass spectrum of the sample to the user. Instead, analyzer 100 displays to the user only a portion (or all) of the information regarding the identity of the sample determined in step 814. For users who have not received special training, information on sample identity is most relevant.

  In addition to the information on the identity of the sample, the controller 108 can also display other information. For example, in some embodiments, the analyzer 100 can access a database of known hazards (eg, stored in storage or accessible via the communication interface 117). If information on the identity of the sample is present in the dangerous substance database, the controller 108 can display a warning message and / or additional information to the user. This alert message can include, for example, information regarding the relative danger of the sample. This additional information may include actions to be taken by the user, including, for example, actions that limit the exposure of the user or others to the material, and other security related actions.

  In some embodiments, the spectrometer 100 is configured to display the mass spectrum of the sample to the user when the control means is activated. Referring to FIG. 8B, the user interface 112 includes control means 824 that displays the mass spectrum of the sample on the display 116 when actuated by the user. The control means 824 allows a person trained in interpreting the mass spectrum to directly view the information measured by the detector 118. This information may be useful, for example, if a clear match between measured mass spectral information and reference information is not obtained. Furthermore, if the analyzer 100 is used for laboratory analysis, for example, the user can activate the control means 824 to infer more detailed chemical information, such as fragmentation of specific ions. In some embodiments, the analyzer 100 is configured to display the mass spectrum of the sample only when the control means 824 is activated by the user and / or after the information on the identity of the sample is displayed. Ru. That is, by configuring the analyzer 100, detailed mass spectrum information is not displayed to the user during normal operation, and the user can view the detailed information only by the operation of the control means 824.

  In some embodiments, control means 824 can be configured to allow for two different modes of operation. For example, when the control means 824 is activated by the user of the analyzer 100 to the first state, information regarding the identity of the sample is displayed to the user when the analysis is completed. When the control means 824 is actuated to the second state, mass spectral information (eg, the amount of ions present as a function of mass to charge ratio) is displayed. Thus, the control means 824 may be in the form of a two-way switch which allows the user to select the desired information display mode during operation of the analyzer. In some embodiments, when the control means 824 is activated to the second state, the analyzer 100 can be configured to display information regarding the identity of the sample in addition to the mass spectral information.

  At step 816, the process shown in the flowchart 800 ends. If this scan is initiated by the user activating the control means 820 at step 802, the analyzer 100 waits for the control means 820 to be activated to start the next scan. Alternatively, if the analyzer 100 is in continuous scan mode, the analyzer 100 waits for a defined time interval and automatically starts the next scan after that time interval has elapsed, or Wait for another external trigger, such as a sensor signal.

  As noted above, in general, the analyzer 100 does not use filters to filter atmospheric gas particles. As a result, when particles of the analyte are introduced into the analyzer, atmospheric gas particles are also introduced, and a mixture of gas particles is formed inside the analyzer 100. Because the spectrometer 100 operates at pressures much higher than the internal pressure of conventional mass spectrometers, and because the components of the analyzer 100 are generally relatively insensitive to atmospheric gas particles, they are disclosed herein. The analyzer can be used to introduce the analyte in a manner not possible with conventional mass spectrometers. In particular, the introduction of the analyte particles can be carried out by continuously drawing in the mixture of the analyte particles and the atmospheric gas particles without filtering them. In some embodiments, the analyzer 100 mixes the mixture of gas particles into the gas path 128 via the sample inlet 124 for at least 10 seconds (eg, at least 15 seconds, at least 20 seconds, at least 30 seconds, at least 45). It can be configured to introduce continuously over at least 1 minute, at least 1.5 minutes, at least 2 minutes, at least 3 minutes, at least 4 minutes, at least 5 minutes) or more.

  As the particles of the analyte are introduced continuously over an extended time, the analyzer 100 adjusts the duty cycle of the ion source 102 so that the ion source 102 extends over an extended time (e.g., part of a period during which analyte particles are introduced) Or all) generate ions. As mentioned above, the duty cycle of the ion source 102 can generally be adjusted to control the time period for which ions are generated (eg, by adjusting the time period 274 of FIG. 2I). In some embodiments, the analyzer 100 adjusts the duty cycle such that ions are emitted from the ion source 102 for 10 seconds or more (eg, 20 seconds or more, 30 seconds or more, 40 seconds or more, 50 seconds or more, 50 seconds or more, 1 minute or more, 1.5) It is configured to be generated continuously for more than 2 minutes, more than 3 minutes, more than 4 minutes, more than 5 minutes.

  As mentioned above, the analyzer 100 achieves both compactness and low power operation by eliminating the power consuming components typically found in conventional mass spectrometers. Of these components, vacuum pumps, especially turbomolecular pumps, are heavy and consume a large amount of power. The spectrometer 100 does not include such a pump, and as a result is much lighter and consumes much less power than conventional mass spectrometers.

  By using pressure adjustment subsystem 120, mass spectrometer 100 operates at an internal gas pressure that is significantly higher than the internal gas pressure of a conventional mass spectrometer. In general, at higher pressures, the resolution of the mass spectrometer is reduced by a variety of mechanisms, including collision-induced line broadening and ion-neutral charge exchange. Therefore, the internal gas pressure in the mass spectrometer should be kept as low as possible in order to obtain as high a resolution mass spectrum as possible.

  However, as mentioned above, useful information about the sample, including information on the identity of the sample, can be obtained by measuring the mass to charge ratio of the sample even though the resolution of the mass spectrometer is below the highest possible value. And can be provided to the user. In particular, a sufficiently accurate match between the measured mass spectral information and the reference information may be obtained if the mass spectrometer 100 operates at a higher internal gas pressure and thus lower resolution than conventional mass spectrometers. Can also be achieved.

  Because mass spectrometer 100 operates at a lower resolution than conventional mass spectrometers, in some embodiments, mass spectrometer 100 has several components to further reduce its overall power consumption. Can be further configured to adaptively adjust the operation of The components are operated adaptively to achieve a target degree of resolution in the measured mass spectral information, or to achieve a sufficient agreement between mass spectral information and reference information on known substances or conditions. .

  FIG. 8C shows a flow chart 850 comprising a series of steps of adaptive operation of the mass spectrometer 100 to achieve sufficient agreement between measured mass spectral information and reference information on known substances or conditions. The target resolution may be set by the user of the mass spectrometer 100 (e.g., by user defined settings or by visual inspection of the measured mass spectral information), automatically by the controller 108. In a first step 852 a scan is initiated in the same manner as described above in connection with step 802. Subsequently, at step 854, the sample is introduced into the analyzer 100 in the same manner as described above in connection with step 804. At step 856, the sample particles are ionized to generate ions, as described above in connection with step 806.

  Subsequently, at step 858, the sample ions ionized by the ion source 102 are detected using the detector 118. Step 858 can be performed without activating the ion trap 104 to capture or selectively eject ions. Instead, in step 858, the ions generated by the ion source 102 pass directly through the end cap electrodes 304 and 306 of the ion trap 104 and impinge upon the detector 118. The voltage source 106 can be configured to apply an electrical potential to the electrodes of the ion source 102 and detector 118 and can create an electric field between the ion source 102 and the detector 118 to facilitate ion migration.

  Next, at step 860, controller 108 determines whether a threshold ion current has been detected by detector 118. The threshold ion current may be a user defined setting of the analyzer 100 and / or a user adjustable setting. Alternatively, the threshold ion current may be determined automatically by analyzer 100 based on, for example, dark current and / or noise measurements at detector 118 by controller 108. If the threshold current has not been reached, sample ionization and sample ion detection continue at steps 856 and 858. Further, if the threshold current is reached, the controller 108 activates the ion trap 104 at step 862 to trap ions and selectively eject them into the detector 118. These ejected ions are measured by detector 118 and their mass spectral information is analyzed by controller 108 at step 864 to determine information about the identity of the sample.

  As part of the analysis of step 864, controller 108 may determine the probability that the measured mass spectral information of the sample results from known materials or conditions. At step 866, the controller 108 compares the determined probability with the threshold probability to determine whether analysis of this mass spectral information is limited by the resolution of the analyzer 100. If this probability is greater than the threshold value, controller 108 displays information about the sample (eg, information about the sample identity and / or sample identity) using display 116, and the process ends at step 870. Do.

  However, if the probability is lower than the threshold probability value at step 866, analysis of this mass spectral information may be limited by the resolution of the analyzer 100. To improve the resolution of the analyzer 100, the controller 108 adaptively adjusts the analyzer configuration before the process returns to step 862.

  The controller 108 is configured to adjust its configuration in various ways to improve the resolution of the analyzer 100. In some embodiments, controller 108 is configured to operate buffer gas source 150 to introduce buffer gas into gas path 128. The introduced buffer gas particles can contain, for example, nitrogen molecules, hydrogen molecules, or atoms of a rare gas such as helium, argon, neon, or krypton. The buffer gas source 150 can include a replaceable cylinder containing buffer gas particles and a valve or buffer gas generator connected to the controller 108 via the control line 127a. The controller 108 can be configured to operate the valve of the buffer gas source 150 such that a controlled amount of buffer gas particles is released to the gas path 128. Once released into the gas path 128, the buffer gas particles mix with the ions generated by the ion source 102 to facilitate trapping and selective ejection of the ions into the detector 118, thus the analyzer 100. Improve the resolution of

  In some embodiments, the controller 108 reduces the internal gas pressure of the analyzer 100 to increase the resolution of the analyzer 100. The controller 108 operates the pressure regulation subsystem 120 via control line 127 d to reduce the internal gas pressure. Alternatively or additionally, the controller 108 can close the valve 129 to reduce the internal gas pressure. In some embodiments, the valves 129 can be alternately opened and closed in a specific duty cycle pulsed manner to reduce the internal gas pressure. In some embodiments, the analyzer 100 can include a number of sample inlets, and the valve 129 can be closed to seal the sample inlet 124 while providing for a smaller diameter sample inlet. Another in-line valve can be opened. By using different sample inlets to reduce the gas pressure in the analyzer 100, no change in pumping speed is necessary. Decreasing the internal gas pressure of the analyzer 100 increases the resolution of the analyzer 100 by reducing the frequency of collisions between the ions in the ion source 102, the ion trap 104, and the detector 118.

  In some embodiments, the controller 108 increases the frequency with which the potential applied to the center electrode 302 changes to improve the resolution of the analyzer 100. By reducing the rate at which the applied potential changes, the rate at which the internal electric field of the electrode 302 changes is also reduced. As a result, the selectivity with which ions are ejected from the ion trap 104 is increased, and the resolution of the analyzer 100 is improved.

  In some embodiments, controller 108 is configured to change the axial field frequency or amplitude in ion trap 104 to change the resolution of analyzer 100. Changes in the axial electric field within the ion trap 104 can move the discharge boundary of the ion trap to extend or reduce the high mass range of the analyzer and to modify the resolution and / or resolution of the analyzer 100.

  In some embodiments, controller 108 is configured to increase the resolution of analyzer 100 by changing the duty cycle of ion source 102. A decrease in ionization time has been experimentally observed to improve the resolution of mass spectrometer 100. Thus, referring to the graph 270 of FIG. 2I, the resolution of the analyzer 100 can be reduced by decreasing the period 274 in which the bias potential 272 is applied to the ion source 102 (eg, reducing the duty cycle of the ion source 102). It can be improved.

  Conversely, reducing the resolution of the analyzer 100 may also be useful in certain circumstances. For example, referring to the graphs 270 and 280 of FIG. 2I, by increasing the time period 274 when the bias potential 272 is applied to the ion source 102 (eg, increasing the duty cycle of the ion source 102), By reducing the period during which the amplitude of the potential applied to the electrode 302 is increased (periods 284 and 286 in graph 280), the resolution of the analyzer 100 is reduced, but the sensitivity of the analyzer 100 is improved, and thus , The signal-to-noise ratio of mass spectral information measured using the analyzer 100 is increased. The sensitivity thus increased can be particularly useful when trying to detect very low concentrations of specific substances.

  In some embodiments, controller 108 increases the resolution of analyzer 100 by increasing the time period (eg, interval 286 in FIG. 2I) that increases the potential applied to electrode 302 of ion trap 104. It is configured. By increasing the sweep period, circulating ions are evacuated from the ion trap 104 more slowly, thereby increasing the resolution of the measured mass spectral information.

  In some embodiments, controller 108 is configured to change the resolution of analyzer 100 by adjusting a ramp profile associated with an amplitude sweep of the potential applied to electrode 302. As shown in graph 280 of FIG. 2I, the amplitude of the potential applied to electrode 302 typically increases according to a linear ramp function. However, more generally, the controller 108 can be configured to increase the amplitude of the potential applied to the electrode 302 according to different ramp functions. For example, the ramp profile can be adjusted by the controller 108 to increase the applied potential according to a series of different linear ramp profiles, each representing the potential increase at a different rate. In another example, the ramp profile can be adjusted so that the amplitude of the potential applied to the electrode 302 increases in accordance with a non-linear function such as an exponential function or a polynomial function.

  As mentioned above, the controller 108 is configured to perform one or more of the operations described above to change the resolution of the analyzer 100. The order in which these operations are performed may be determined by the analyzer 100 or may be determined by user preferences. For example, in some embodiments, a user of the analyzer 100 can increase the resolution of the analyzer 100 and / or reduce power consumption by the analyzer in any of the above-described steps, in which order You can specify whether to execute. Such user selections may be stored on storage device 114 as a set of preferences. Alternatively, in some embodiments, the order of operations performed by controller 108 may be permanently encoded in the logic circuitry of controller 108 or stored in storage 114 as a non-modifiable setting It is also good.

  In some embodiments, controller 108 can determine the order of operations based on other considerations. For example, to ensure that power consumption of the analyzer 100 is minimized, the order of operations performed by the controller 108 to improve the resolution of the analyzer 100 can be determined as the power consumption increases as a result of each operation. The controller 108 can be configured with information on how each operation described above increases the overall power consumption, and based on this power consumption information can select the proper sequence of operations, which increases the power consumption. The minimum action is taken first. Alternatively, controller 108 can be configured to measure the increase in power consumption associated with each operation, and can further select the order of operations based on the measured power consumption values.

  In flow chart 850, the adjustment of the configuration of the analyzer 100 is based on the probability that the measured mass spectral information matches the known reference information, while the adjustment of the configuration of the analyzer 100 is based on other criteria. It is also good. In some embodiments, for example, adjusting the configuration of the analyzer 100 can also be based on whether the target resolution of the analyzer 100 is achieved. At step 864, controller 108 determines the actual resolution of analyzer 100 based on the measured mass spectral information (eg, based on the FWHM of a single ion peak within the measurement window of analyzer 100). At step 866, the actual resolution is compared to the target resolution of the analyzer 100 by the controller. If the actual resolution is lower than the target resolution, then in step 872 controller 108 adjusts the configuration of the analyzer to improve the resolution of analyzer 100 as described above.

Hardware, Software, Electronic Processing Any of the method steps, features and / or attributes disclosed herein may be based on controller 108 (eg, electronic processor 110 of controller 108) and / or standard programming techniques. The program may be executed by one or more additional electronic processors (eg, a computer or programmed integrated circuit) executing the program. Such a program may comprise a programmable computing device or a special device, each comprising a processor, a data storage system (including memory and / or storage elements), at least one input device, and at least one output device such as a display or printer. It is designed to run on integrated circuits designed for Program code is applied to input data to perform output functions that execute functions and apply to one or more output devices. Each such computer program is preferably implemented in a high level procedural or object oriented programming language or assembly or machine language. Furthermore, these languages may be compiled or translated languages. Each such computer program may be stored on a computer readable storage medium (eg, a CD-ROM or magnetic disk) that, when read by a computer, causes the processor of the computer to perform the analysis and control functions described herein. .

Other Embodiments In some embodiments, the analyzer 100 is configured to operate even at high gas pressures, eg, up to 1 atmosphere (eg, 760 Torr). That is, one or more of the internal gas pressures of the ion source 102, ion trap 104, and / or detector 118 may be 100 Torr and 760 Torr when the analyzer 100 detects ions according to the mass to charge ratio of the ions. (E.g., 200 torr, 300 torr, 400 torr, 500 torr, 600 torr).

  Some of the components disclosed herein are already suitable for operation at pressures up to one atmosphere (and higher). For example, some of the ion sources disclosed herein, such as glow discharge ion sources, can operate at pressures up to one atmosphere with little or no modification. Furthermore, certain detectors such as Faraday detectors (eg, Faraday cup detectors and arrays thereof) can operate at pressures up to 1 atmosphere with little or no modification.

The ion trap disclosed herein can be adapted to operate at pressures up to 1 atmosphere. For example, referring to FIG. 3A, to operate at a pressure of 1 atmosphere, the dimension c ₀ of the ion trap 104 is between 1.5 and 0.5 microns (eg, between 1.5 and 0.7 microns, 1.2 microns and so on) It should be reduced to between 0.5 microns, 1.2 microns and 0.8 microns, roughly 1 micron). Furthermore, to operate at a gas pressure of up to 1 atm, the voltage source 106 has a frequency in the GHz range, for example, a frequency of 1.0 GHz or more (for example, 1.2 GHz or more, 1.4 GHz or more, 1.6 GHz or more, 2.0 GH or more, 2.0 GH or more, 5.0) The ion trap 104 can be modified to apply a sweep voltage that repeats at or above GHz). This retrofit of the ion trap 104 and voltage source 106 allows the mass spectrometer 100 to operate at pressures up to one atmosphere, greatly reducing the use of the pressure regulation subsystem 120. In some embodiments, it may also be possible to remove the pressure regulation subsystem 120 from the analyzer 100, for example, such that the analyzer 100 is a pumpless analyzer.

  Several embodiments have been described. However, it will be understood that many modifications are possible without departing from the spirit and scope of the present disclosure. Accordingly, other embodiments are within the scope of the following claims.

Claims (1)

An ion source,
Ion trap,
An ion detector,
A mass spectrometer including a gas pressure control subsystem;
During operation of the mass spectrometer
The gas pressure regulation subsystem is configured to maintain a gas pressure between 100 mTorr and 100 Torr in at least two of the ion source, the ion trap, and the ion detector.
The mass spectrometer, wherein the ion detector is configured to detect ions generated by the ion source according to a mass to charge ratio of the ions.