JP5206005B2 - Mass spectrometer - Google Patents

Description

  The present invention relates to a mass spectrometer, and more particularly, to a mass spectrometer equipped with an atmospheric pressure ion source suitable for combination with a liquid chromatograph.

  In a liquid chromatograph mass spectrometer (LC / MS), an eluate containing a sample whose components have been separated by a liquid chromatograph column is introduced into an atmospheric pressure ion source such as electrospray to ionize the generated ions. For example, it is separated and detected according to the mass (strictly, the mass to charge ratio m / z) by a mass separator such as a quadrupole mass filter. In order to improve the analysis sensitivity in such an apparatus, it is important to efficiently transport ions generated under a substantially atmospheric pressure atmosphere to a mass separator disposed in a high vacuum atmosphere.

  For example, in LC / MS described in Patent Document 1 and the like, a desolvation tube that transports ions from an ionization chamber that is substantially at atmospheric pressure to the next intermediate vacuum chamber, a deflector electrode disposed in the intermediate vacuum chamber, and the like The ion transport efficiency greatly depends on the voltage applied to the. The applied voltage that can achieve the best ion transport efficiency also varies depending on the mass-to-charge ratio of ions passing therethrough. Therefore, in the LC / MS described in Patent Document 1, the applied voltage that maximizes the peak of the mass spectrum for each mass-to-charge ratio is examined and stored by preliminary measurement using a standard sample. When measuring the sample, an appropriate applied voltage is set based on the stored information. Thereby, irrespective of the mass-to-charge ratio of the measurement object, the ion transport efficiency is improved, and high analytical sensitivity can be achieved.

  The preliminary measurement in the adjustment operation of the optimum voltage as described above is generally performed using a standard sample prepared by an apparatus manufacturer or the like that contains a known component at a known concentration. However, since these standard samples do not cover all the components that the user wants to analyze, some users perform automatic adjustments using target samples prepared by themselves (usually samples whose components are known). There is a strong demand for it. In these samples other than the standard sample, the concentration of the component may be extremely low, or conversely too high. Under such circumstances, the effects of sudden noise appear relatively large and the chromatogram becomes unclear. The optimal voltage may not be set properly. As a result, a non-optimal voltage is automatically set as the analysis condition, and the analysis sensitivity may be lowered.

Japanese Patent No. 3478169

  The present invention has been made in order to solve the above-mentioned problems, and the object of the present invention is that even when a non-standard sample is used, even when an inappropriate voltage may be set, An object of the present invention is to provide a mass spectrometer capable of setting analysis conditions for efficiently transporting ions by eliminating the influence of unwanted noise and the unclearness of chromatograms.

The present invention, which has been made to solve the above-mentioned problems, comprises an atmospheric pressure ion source that ionizes components in a liquid sample under a substantially atmospheric pressure atmosphere, and a high-pressure atmosphere to ionize mass charges. A mass separator that separates according to a ratio; a detector that detects ions separated by the mass separator; and a plurality of ion transport optical systems that transport ions from the atmospheric pressure ion source to the mass separator; In a mass spectrometer comprising:
a) When mass analysis is performed on a predetermined adjustment sample, and the voltage applied to at least one of the plurality of ion transport optical systems is changed in a plurality of stages for each mass to charge ratio of one to a plurality of measurement objects Adjustment measurement execution means for acquiring the signal intensity by the detector;
b) Based on the measurement result obtained by the adjustment measurement execution means, the relationship between the voltage applied to the ion transport optical system and the signal intensity or the calculated value obtained from the signal intensity is obtained for each mass-to-charge ratio of the measurement object. In addition to displaying the voltage and the signal intensity or the calculated value on the display screen as a graph with two axes, the voltage applied to the at least one ion transport optical system is changed in multiple stages for each mass-to-charge ratio of the measurement object. Each of the applied voltages, a chromatogram showing the temporal change in signal intensity before and after the sample is introduced into the atmospheric pressure ion source is created, and the waveforms of the plurality of chromatograms are generated. Data processing means for displaying on the display screen together with the graph as reference information for the user to determine the optimum voltage condition ;
c) For the user to instruct a voltage value by instructing an applied voltage that can be regarded as optimum on the graph displayed together with the plurality of chromatograms for each mass-to-charge ratio to be measured, or for the signal intensity Or input means for changing the voltage value of the optimum applied voltage automatically determined from the calculated value;
d) Analysis condition setting means for setting the voltage indicated or changed by the input means as analysis voltage as an applied voltage to the mass-to-charge ratio in the at least one ion transport optical system;
It is characterized by having.

  Here, the atmospheric pressure ion source is, for example, an electrospray ion source (ESI), an atmospheric pressure chemical ion source (APCI), an atmospheric pressure photoion source (APPI), or the like.

  The adjustment sample may be a standard sample containing a known component at a known concentration (usually a sufficiently prepared appropriate concentration), or may be a target sample itself to be measured prepared by a user. Absent.

  As one aspect of the mass spectrometer according to the present invention, the ion transport optical system whose applied voltage can be changed by the adjustment measuring means transports ions from the ionization chamber, which is a substantially atmospheric pressure atmosphere, to the next intermediate vacuum chamber. It can be set as the structure which is any one or both of a small diameter desolvation pipe | tube and the ion guide arrange | positioned in this intermediate | middle vacuum chamber.

  In the mass spectrometer according to the present invention, the adjustment measurement execution means appropriately sets, for example, an applied voltage to the desolvation tube and an applied voltage to the ion guide for each designated mass (mass-to-charge ratio). The signal intensity is collected by performing mass analysis on the adjustment sample while changing the voltage step width. For example, when a liquid sample is introduced into an ion source using the flow of a mobile phase, the sample diffuses slightly in time, so a chromatogram (mass chromatogram) showing a temporal change in signal intensity before and after the introduction of the sample. Can be drawn for each mass-to-charge ratio to be measured and for each applied voltage. In this case, the height and area of the peak of the chromatogram can be obtained and used as the calculated value obtained from the signal intensity.

  The data processing means graphs the relationship between the applied voltage and the signal intensity or the calculated value. Usually, the voltage that gives the maximum signal strength or calculated value in this graph is the optimum voltage. However, depending on the component concentration of the sample for adjustment, the waveform of the chromatogram may be disturbed due to the effects of sudden noise, etc., and the actual signal strength should be small, but the signal strength or calculated value may be shown erroneously. There is. In the mass spectrometer according to the present invention, the data processing means displays the graph on the display screen when the graph is obtained.

  The user sees this, for example, judges whether the relationship between the applied voltage and the signal intensity or the calculated value is not unnatural, etc. Indicates the voltage. Alternatively, if the optimum applied voltage is automatically determined from the maximum signal strength or calculated value and specified, it can be set to another voltage that is actually considered optimum, if necessary. change. The analysis condition setting means sets the voltage instructed or changed by the input means to the analysis condition as an applied voltage with respect to its mass-to-charge ratio in, for example, a desolvation tube or ion guide.

Further, the user, simply by looking at the graph showing the relationship between the applied voltage and the signal strength or calculated values, in some cases can not be determined whether the result is unnatural point or abnormality, in the present invention In such a mass spectrometer, since the chromatogram waveform when the applied voltage is changed is displayed as reference information for the user to determine the optimum voltage condition, it is easy to make such a determination.

  For example, in general, a plurality of chromatogram waveforms obtained by changing the applied voltage with respect to the same mass-to-charge ratio are relatively similar in shape as a whole waveform although peak intensities and the like are different. Therefore, when the chromatogram waveform is abnormally disturbed, it can be determined that there is a high possibility of noise, and when the peak top is crushed or abnormally distorted, It can be determined that the component concentration may be too high.

  Therefore, in the mass spectrometer according to the present invention, ion transport optics such as a desolvation tube and an ion guide are automatically or based on the result of mass spectrometry performed by the adjustment measurement execution unit, that is, without involving the user. The voltage to be applied to the system is not determined, but the user can confirm it and easily specify or change an appropriate voltage. Thereby, even when the sample used in the adjustment measurement is not ideal, an appropriate applied voltage to each ion transport optical system can be determined as one of the analysis conditions for each mass-to-charge ratio of the measurement target. As a result, high analytical sensitivity can be achieved.

  Note that, in the mass spectrometer according to the present invention, several events that the user judges by looking at the graph displayed on the display screen can be automatically detected. For example, for the same mass-to-charge ratio, the similarity (coincidence) of a plurality of chromatogram waveforms obtained by changing the applied voltage is digitized, and it is determined that the numerical value is below a certain threshold and the similarity is low. If there is a chromatogram, the optimum voltage can be determined by eliminating it. By providing an anomaly detection means that executes part or all of the user's judgment instead, the user's involvement by the input means is eliminated, or everything is automated, or the user is involved with leaving the input means. However, it is possible to reduce the burden on the user.

  Hereinafter, a liquid chromatograph mass spectrometer (LC / MS) which is an embodiment of the present invention will be described in detail with reference to FIGS. FIG. 1 is a configuration diagram of a main part of the LC / MS according to the present embodiment.

  In the liquid chromatograph (LC) unit 1, the liquid feed pump 11 sucks the mobile phase stored in the mobile phase container 10 and sends it to the column 13 through the injector 12 at a substantially constant flow rate. When the sample is injected by the injector 12, the sample is introduced into the column 13 along the flow of the mobile phase, and various components in the sample are separated while passing through the column 13, and are shifted in time. Elute from the outlet. A flow path switching valve 14 is provided at the outlet of the column 13, and the eluate from the column 13 is introduced into the mass spectrometry (MS) unit 2 through the valve 14 during normal analysis.

  An adjustment sample introduction unit 15 is connected to the other side of the valve 14, and the sample solution from the adjustment sample introduction unit 15 is introduced into the MS unit 2 by switching the valve 14 during automatic voltage adjustment as described later. However, the method for introducing the adjustment sample is not limited to this. For example, the adjustment sample may be injected into the mobile phase by the injector 12 and the components may be separated by the column 13. Alternatively, a bypass channel may be provided in which the mobile phase in which the adjustment sample is injected by the injector 12 flows around the column 13, and the mobile phase passing through the bypass channel may be introduced into the MS unit 2.

  The MS unit 2 includes a first intermediate vacuum chamber 23 and a second intermediate vacuum chamber 20 between an ionization chamber 20 having a substantially atmospheric pressure atmosphere and an analysis chamber 28 having a high vacuum atmosphere evacuated by a high performance vacuum pump (not shown). This is a configuration of a multistage differential exhaust system in which two chambers of the intermediate vacuum chamber 26 are provided. The ionization chamber 20 and the first intermediate vacuum chamber 23 are communicated with each other by a small-sized desolvation tube 22, and the first intermediate vacuum chamber 23 and the second intermediate vacuum chamber 26 are provided at the top of the skimmer 25. It communicates through a very small diameter passage hole (orifice).

  In the MS unit 2, the eluate containing the sample component is sprayed into the ionization chamber 20 in a substantially atmospheric pressure atmosphere while being charged in the electrospray unit 21, whereby the sample component is ionized. It should be noted that ionization may be performed using other atmospheric pressure ionization methods such as atmospheric pressure chemical ionization instead of electrospray ionization. Ions generated in the ionization chamber 20 and fine droplets in which the solvent has not yet completely evaporated are drawn into the desolvation tube 22 by the differential pressure, and further finer while passing through the heated desolvation tube 22. Ions are generated as the solvent evaporates from the droplets.

  In the first intermediate vacuum chamber 23, there is a first ion guide 24 in which a plurality of four electrode plates surrounding the ion optical axis C in a plane orthogonal to the ion optical axis C are arranged in the ion optical axis C direction. Is provided. The ions are converged by the first ion guide 24, pass through the orifice, and enter the second intermediate vacuum chamber 26. The second intermediate vacuum chamber 26 is provided with a second ion guide 27 composed of eight rod electrodes arranged so as to surround the ion optical axis C. The ions are converged by the second ion guide 27 and are analyzed. Is sent to. In the analysis chamber 28, a quadrupole mass filter 30 composed of four rod electrodes and a pre-rod electrode 29 composed of four rod electrodes that are short in the direction of the ion optical axis C in the preceding stage are disposed. . Of the various ions, only ions having a specific mass-to-charge ratio pass through the quadrupole mass filter 30 and reach the ion detector 31.

  A detection signal from the ion detector 31 is input to the data processing unit 37, and various data processing such as creation of a mass spectrum, a mass chromatogram, and a total ion chromatogram is executed. The analysis control unit 38 controls the operation of each unit of the LC unit 1 and the MS unit 2 including the power supply units 32 to 36 described later in order to perform LC / MS analysis based on an instruction from the central control unit 39. . The central control unit 39 is connected to an input unit 40 as a user interface, a display unit 41, and a printer 42, and receives various operations for analysis in response to an operation of the operator by the input unit 40, the analysis control unit 38 and the data. While outputting to the process part 37, the analysis results, such as a mass spectrum, are output to the display part 41 and the printer 42. FIG. Note that most of the central control unit 39, the analysis control unit 38, and the data processing unit 37 can be realized by a personal computer equipped with predetermined control / processing software.

  Each rod electrode of the quadrupole mass filter 30 is applied with a voltage V5 obtained by adding a predetermined DC bias voltage to a voltage obtained by superimposing a high frequency voltage and a DC voltage from the fifth power supply unit 36, and this high frequency voltage. The mass-to-charge ratio that can pass through is determined according to the DC voltage. A predetermined DC bias voltage V1 is applied to the desolvation tube 22 from the first power supply unit 32, and a voltage V2 obtained by adding the DC bias voltage to the predetermined high-frequency voltage from the second power supply unit 33 to the first ion guide 24. Is applied to the second ion guide 27, and a voltage V3 obtained by adding a DC bias voltage to a predetermined high-frequency voltage is applied to the second ion guide 27. Furthermore, a voltage V4 obtained by adding a predetermined DC bias voltage to the voltage obtained by superimposing the high-frequency voltage and the DC voltage from the fourth power supply unit 35 is applied to the prerod electrode 29. In addition, a DC bias voltage is actually applied to the skimmer 25 and the like in addition to that, but only representative ones are shown here in order to avoid complicated description.

  Here, paying attention to the transport efficiency of ions from the ionization chamber 20 to the second intermediate vacuum chamber 26, in order to make the transport efficiency of the ions as high as possible, the first power supply unit 32 connects to the desolvation tube 22. It is important to appropriately set the applied DC bias voltage V1 and the DC bias voltage applied from the second power supply unit 33 to the second ion guide 24 in accordance with the mass-to-charge ratio of ions passing therethrough. Therefore, the LC / MS of this embodiment has a characteristic automatic voltage adjustment function. Next, the operation when executing this automatic voltage adjustment will be described.

  FIG. 2 is a flowchart showing a processing / control procedure when automatic voltage adjustment is executed. First, the operator performs a predetermined operation using the input unit 40 to input and set analysis conditions for SIM (selected ion monitoring) measurement and voltage adjustment execution conditions (step S1). The SIM measurement analysis conditions include, for example, one or more m / z values (mass-to-charge ratio) to be subjected to SIM measurement, the temperature of each part of the apparatus, and the like, which are conditions at the time of measuring a target sample.

  On the other hand, in order to set the voltage adjustment execution condition, first, a predetermined operation is performed by the input unit 40 to display the voltage adjustment execution setting window 50 shown in FIG. 3 on the screen of the display unit 41. Then, the type of the target (ion transport optical system) for voltage optimization, the adjustment range of the voltage value and the number of voltage steps, the type of data used for determining the optimum value, etc. are set. In the example shown in FIG. 3, the optimization target is a DC voltage applied to the Q array (first ion guide 24), the voltage value adjustment range is 0 to 80 [V], and the number of voltage steps Is 5 and the height or area of the chromatogram peak is used to calculate the optimum value.

  When the operator clicks the “start” button 51 after setting necessary conditions and parameters in the voltage adjustment execution setting window 50, the central control unit 39 receives this and starts a voltage adjustment operation for voltage optimization. (Step S2). First, based on the various conditions and parameters set as described above, an analysis method file for executing analysis is created (step S3), and the analysis control unit 38 executes actual measurement according to the method file. (Step S4).

  In order to simplify the explanation, consider the case where the DC voltage applied to the second ion guide 24 is changed in 10 [V] steps in the range of 0 to 50 [V], and the m / z value of the SIM measurement target. Are three of M1, M2, and M3. In this case, first, m / z = M1 is changed in order of V1 = 0, 10, 20, 30, 40, and 50 [V], and the samples prepared in the adjustment sample introduction unit 15 are respectively measured. Thereafter, the m / z value is changed in order of M2 and M3, and the measurement for each applied voltage is similarly performed. Alternatively, in a state where the applied voltage is fixed at V1 = 0, measurement is performed by changing m / z = M1 → M2 → M3 in order, and after the measurement is completed, V1 = 10 [V] and the same measurement is performed. It may be repeated. In any case, the measurement for the same adjustment sample may be executed for all the combinations of m / z values and applied voltages that have been set.

  The adjustment target sample set by the user is introduced from the adjustment sample introduction unit 15 into the MS unit 2 on the mobile phase, and the data processing unit 37 pays attention based on the detection signal from the ion detector 31. A mass chromatogram showing the temporal change in signal intensity at the m / z value is created. Then, peak detection is performed on the chromatogram, and for example, the peak area value is calculated. This area value is a calculated value in the present invention. The mass chromatogram is obtained for each m / z value and each applied voltage, and the area value is obtained. Compare the area values obtained by changing the voltage value for the same m / z value, and find the largest area value. Is set as a provisional optimum voltage value (step S5).

  Next, for each m / z value, the data processing unit 37 creates a voltage-intensity correspondence graph 61 with the horizontal axis representing the voltage value and the vertical axis representing the peak area value, including this graph 61, as shown in FIG. The optimization result window 60 is displayed on the screen of the display unit 41 (step S6). The optimization result window 60 also includes a chromatogram 62 obtained for each voltage value. Further, the optimum voltage value (40.0 V in this case) automatically determined as described above is also displayed in the window 60 (reference numeral 63). The operator checks the voltage-intensity correspondence graph, the chromatogram shape at each voltage, and the like on this screen, and determines whether or not the optimum voltage value set automatically is appropriate. For example, in the case of the result shown in FIG. 4, when looking at the curve of the voltage-intensity correspondence graph 61, the optimum voltage value 40V is the peak, and the area value spreads in a skirt shape on both the low voltage side and the high voltage side. Yes. Further, the waveform shape of the chromatogram 62 is hardly disturbed and is relatively similar regardless of the voltage value. Therefore, it can be determined that the automatically set optimum voltage value is appropriate.

  For example, FIG. 5 shows an example of the optimization result when sudden noise occurs. In this case, the voltage-intensity correspondence graph 61 has two peaks, which is unnatural. Further, although 10 [V] is automatically set as the optimum voltage value, the waveform of the chromatogram 62 ′ corresponding to the voltage value has a clear disturbance different from the case of other voltage values. . Therefore, it can be estimated that there is a high possibility that the optimum voltage value is abnormal. When the operator determines that 40 [V] is the optimum voltage value, the vicinity of the peak top with respect to the optimum voltage value is displayed on the graph 61 ′. Double-click on the input unit 40. Upon receiving this operation, the central control unit 39 recognizes that the optimum setting value has been changed, and changes the provisional optimum voltage value that has been automatically set (step S7).

  Regardless of whether or not there is a change in step S7, when the operator clicks the “apply to method” button 64, the central control unit 39 receives this operation and determines the optimum voltage value determined at that time. This is reflected in the analysis conditions of the SIM measurement (step S8). Thereby, the condition of the DC voltage of the first ion guide 24 at the designated m / z value is determined. Further, for other m / z values, it is possible to determine whether or not the optimum voltage value automatically set by the same operation is appropriate, and to change it as necessary.

  Further, when the operator clicks the “print” button 65 at this time, the central control unit 39 which has received this operation has the m / z value and the optimum voltage value information as shown in FIG. Output the result. Thereby, for example, the voltage-intensity correspondence graph used when the operator changes the m / z value can be left as a paper record. Of course, such information can be stored in an arbitrary storage device in the form of an electronic file.

  Furthermore, the voltage applied to another ion transport optical system, for example, the desolvation tube 22 can be determined in the same procedure. In addition, when the schedule is set to execute the measurement of the target sample following the automatic adjustment, the measurement may be automatically started according to the SIM measurement conditions.

  Displaying the optimization result and requesting confirmation from the operator as described above is also useful in the following cases. When the optimization result window 60 as shown in FIG. 6 is displayed, it can be readily seen from the voltage-intensity correspondence graph 61 ″ that the maximum voltage in the adjustment range is the optimum voltage value. This indicates that there is a possibility that the initial optimization condition is not properly set and there is an optimum voltage value outside the adjustment range set there. Therefore, it is not desirable to determine the optimum voltage value at this stage, and the operator can select to change the optimization condition and perform adjustment again.

  In the above embodiment, the operator determines the abnormality and changes the optimum voltage value, but if this can be automated, the burden on the operator can be reduced and the operator's experience and skill level can be affected. Appropriate voltage conditions can be determined without receiving. For example, it can be determined that there is a high possibility that the automatically set optimum voltage value is not appropriate by the following data processing based on the voltage-intensity correspondence graph and the mass chromatogram at each voltage.

  That is, as described above, in the voltage-intensity correspondence graph, a peak top appears at a certain voltage value, and the intensity decreases substantially uniformly on the low voltage side and the high voltage side, or a substantially flat peak. It is envisaged that the top will have a shape that continues over a voltage range, etc. For example, when two peaks appear clearly as shown in FIG. 5 or when there is only a uniform increase or a uniform decrease as shown in FIG. 6, it can be determined that there is a high possibility of abnormality. Therefore, by automatically making such a determination, information on the voltage value that can be clearly determined to be abnormal is removed and the optimum voltage value is determined, or information that is highly likely to be abnormal For example, it is possible to call the operator's attention by specifying the different display colors or the like.

  In general, the peak waveforms of chromatograms obtained when the voltage value is changed are similar as shown in FIG. Therefore, waveform processing such as enlargement / reduction, distortion correction, etc. is performed to calculate an index value indicating the similarity of the waveform shape. If the index value is below a certain threshold, the measurement at the time of acquiring the chromatogram is abnormal. It is judged that. By such processing, for example, it can be determined that the chromatogram at a voltage of 10 [V] shown in FIG. 5 is abnormal. Therefore, except for this information, it is possible to eliminate the influence of noise and the like by setting the optimum voltage value using only the area values at other voltage values.

  It should be noted that the above embodiment is merely an example of the present invention, and it should be understood that modifications, corrections, and additions may be made as appropriate within the scope of the present invention and included in the scope of the claims of the present application.

The block diagram of the principal part of LC / MS by one Example of this invention. The flowchart which shows the procedure of the process and control at the time of the automatic voltage adjustment in LC / MS of a present Example. The figure which shows an example of a voltage adjustment execution setting window. The figure which shows an example of a display of an optimization result window. The figure which shows an example of a display of an optimization result window. The figure which shows an example of a display of an optimization result window. The figure which shows an example of the paper output of an optimization result.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Liquid chromatograph (LC) part 10 ... Mobile phase container 11 ... Liquid feed pump 12 ... Injector 13 ... Column 14 ... Valve 15 ... Sample introduction part 2 for adjustment ... Mass spectrometry (MS) part 20 ... Ionization chamber 21 ... Electro Spray section 22 ... Desolvation tube 23 ... First intermediate vacuum chamber 24 ... First ion guide 25 ... Skimmer 26 ... Second intermediate vacuum chamber 27 ... Second ion guide 28 ... Analysis chamber 29 ... Prerod electrode 30 ... Quadrupole mass Filter 31 ... Ion detectors 32 to 36 ... Power supply part 37 ... Data processing part 38 ... Analysis control part 39 ... Central control part 40 ... Input part 41 ... Display part 42 ... Printer 50 ... Voltage adjustment execution setting window 60 ... Optimization result Windows

Claims (2)

An atmospheric pressure ion source that ionizes components in a liquid sample under a substantially atmospheric pressure atmosphere, a mass separator that is disposed in a high vacuum atmosphere and separates ions according to a mass-to-charge ratio, and the mass separation In a mass spectrometer comprising: a detector that detects ions separated by a detector; and a plurality of ion transport optical systems that transport ions from the atmospheric pressure ion source to the mass separator.
a) When mass analysis is performed on a predetermined adjustment sample, and the voltage applied to at least one of the plurality of ion transport optical systems is changed in a plurality of stages for each mass to charge ratio of one to a plurality of measurement objects Adjustment measurement execution means for acquiring the signal intensity by the detector;
b) Based on the measurement result obtained by the adjustment measurement execution means, the relationship between the voltage applied to the ion transport optical system and the signal intensity or the calculated value obtained from the signal intensity is obtained for each mass-to-charge ratio of the measurement object. In addition to displaying the voltage and the signal intensity or the calculated value on the display screen as a graph with two axes, the voltage applied to the at least one ion transport optical system is changed in multiple stages for each mass-to-charge ratio of the measurement object. Each of the applied voltages, a chromatogram showing the temporal change in signal intensity before and after the sample is introduced into the atmospheric pressure ion source is created, and the waveforms of the plurality of chromatograms are generated. Data processing means for displaying on the display screen together with the graph as reference information for the user to determine the optimum voltage condition ;
c) For the user to instruct a voltage value by instructing an applied voltage that can be regarded as optimum on the graph displayed together with the plurality of chromatograms for each mass-to-charge ratio to be measured, or for the signal intensity Or input means for changing the voltage value of the optimum applied voltage automatically determined from the calculated value;
d) Analysis condition setting means for setting the voltage indicated or changed by the input means as analysis voltage as an applied voltage to the mass-to-charge ratio in the at least one ion transport optical system;
A mass spectrometer comprising:   2. The mass spectrometer according to claim 1, wherein the ion transport optical system whose applied voltage can be changed by the adjustment measurement execution unit transports ions from an ionization chamber having a substantially atmospheric pressure atmosphere to a next intermediate vacuum chamber. A mass spectrometer comprising any one or both of a small-diameter desolvating tube and an ion guide disposed in the intermediate vacuum chamber.

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