JP5378307B2 - Detector for liquid chromatography - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a detector for a liquid chromatograph capable of increasing a light intensity level as much as possible within a range where an optical sensor is not saturated while taking into consideration variations in characteristics of a light source and an optical component. <P>SOLUTION: The detector for the liquid chromatograph includes: a light source which makes light incident on a flow cell; an optical sensor which detects light transmitting through the flow cell; an opening member having an opening which is provided between the light source and the optical sensor and through which the light is transmitted; a movement unit which moves the opening member in the optical axis direction; and a control unit which sends an instruction to move the opening member in the optical axis direction on the basis of light intensity detected by the optical sensor. <P>COPYRIGHT: (C)2012,JPO&amp;INPIT

Description

  The present invention relates to a detector used in a liquid chromatograph.

  A liquid chromatograph is an optical means for circulating a liquid called a mobile phase containing a target component through a cylindrical tube filled with microparticles called a column, and separating or purifying the target component separated or purified when passing through the column. It is an apparatus which detects using. A liquid chromatograph is usually separated or purified by a pump for feeding a liquid, a sampler for introducing a sample into the liquid, a column oven for holding the column in a constant temperature atmosphere, and the column. It comprises a detector for detecting a sample, a data processing device for creating a chromatogram from data detected by the detector, and a control device for controlling the operation of the above devices. Since multiple components of the sample introduced from the sampler are separated by the column and pass through the detector at different times, the detector uses optical means to measure the concentration change of the target component contained in the mobile phase. To detect.

  As a liquid chromatograph detector, a UV detector that measures absorbance by ultraviolet light is widely used. In the UV detector, a deuterium lamp that emits ultraviolet light including light having a wavelength of 190 to 400 nanometers is used as a light source. A UV detector generally performs detection as follows. First, ultraviolet light emitted from a deuterium lamp is dispersed by a grating. Only light of a specific wavelength is extracted from the split light using a slit. The extracted light of a specific wavelength is condensed by a lens, a curved mirror, or the like, and irradiated to the flow path in which the mobile phase flows. A flow path irradiated with light is called a flow cell. The light transmitted through the flow cell is received by an optical sensor and converted into an electrical signal. Since the intensity of the transmitted light that passes through the flow cell depends on the concentration of the target component contained in the mobile phase flowing through the flow cell, the concentration of the target component that passes through the flow cell is the intensity of the electrical signal in the photocell of the photosensor. Finally detected.

  Similarly, there is a diode array detector as a detector for detecting a target component with light. The UV detector irradiates the flow cell with the dispersed light and measures the absorbance at each wavelength, while the diode array detector irradiates the flow cell with light that contains the unspectrulated multi-wavelength component, The transmitted light is dispersed by a grating and detected for each wavelength by a photodiode array composed of a plurality of photodiodes. The diode array detector has an advantage that a plurality of wavelengths can be detected simultaneously.

  A photocell of an optical sensor used for the UV detector and a photodiode used for the diode array detector are both optical sensors that convert light into an electrical signal, and output an electrical signal corresponding to the light intensity. There is a limit to the light intensity detection range of this optical sensor, and when the light intensity exceeds a certain level, the output electric signal is saturated. For this reason, it is necessary to devise such that detection is performed at a light intensity level that does not saturate the optical sensor.

  For the purpose of changing the light intensity from the light source, a configuration in which the slit member is taken in and out, the opening diameter is changed, the slit width is changed, and the transmittance of the liquid crystal filter is changed is known (for example, Patent Document 1). However, there is no one that solves the problem of setting the light intensity level in consideration of the saturation of the optical sensor.

  Normally, detection is performed at a light intensity level that does not saturate the optical sensor. On the other hand, if the light intensity level is low, the sensitivity required to detect the target component cannot be obtained. In addition, in consideration of variations in characteristics of the light source and optical components, the light intensity level must be lowered to the safe side. For this reason, there is a demand for a technique capable of raising the light intensity level as much as possible within a range in which the optical sensor is not saturated while taking into account variations in characteristics of the light source and the optical components.

Japanese Patent Laid-Open No. 11-83828

  An object of the present invention is to provide a detector for a liquid chromatograph capable of raising the light intensity level as much as possible within a range where the optical sensor is not saturated while taking into account variations in the characteristics of the light source and optical components. To do.

  In order to solve the above-described problems, an embodiment of the present invention includes a light source that causes light to enter the flow cell, a light sensor that detects light that has passed through the flow cell, and an opening that is provided between the light source and the light sensor. An opening member having an opening member, a moving device that moves the opening member in the optical axis direction, and a control device that sends a command to move the opening member in the optical axis direction based on the light intensity detected by the optical sensor. It is characterized by.

  According to an embodiment of the present invention, there is provided a detector for a liquid chromatograph capable of increasing the light intensity level as much as possible within a range in which the optical sensor is not saturated while taking into account variations in characteristics of light sources and optical components. can do.

It is a block diagram which shows the main structures of the detector for liquid chromatographs. It is a block diagram which shows the main structures of the detector for liquid chromatographs. It is a block diagram which shows the main structures of the detector for liquid chromatographs. It is a block diagram which shows the main structures of the detector for liquid chromatographs. It is a block diagram which shows the structure of the moving apparatus of an opening member. It is a flowchart which shows the position adjustment procedure of an opening member.

  Embodiments of the present invention will be described below with reference to the drawings.

〔Example〕
FIG. 1 is a block diagram showing the main configuration of a liquid chromatograph detector, and explains the principle of the present invention. The light emitted from the light source 101 is condensed on the flow cell 103 through which the sample passes by the incident side condensing optical device 102. The transmitted light that has passed through the flow cell 103 is condensed on the optical sensor 105 by the detection-side condensing optical device 104, and the data detected by the optical sensor 105 is sent to a data processing device (not shown). An aperture member 106 is disposed between the incident-side condensing optical device 102 and the flow cell 103 to limit the light intensity incident on the flow cell 103. The opening member 106 is attached to the moving device 107 and is movable in the optical axis direction. While checking the light intensity of the transmitted light detected by the optical sensor 105, the optical sensor 105 is not saturated, and The light intensity can be adjusted to be high. Since the light source 101, the incident-side condensing optical device 102, and the detection-side condensing optical device 104 have characteristic variations that cannot be avoided in the manufacturing process, the light intensity is increased or decreased by adjusting the position of the aperture member 106. Can be absorbed. Further, since the light intensity generated by the light source 101 decreases with time, the light intensity can be kept high by adjusting the position of the opening member 106.

  FIG. 2 is a configuration diagram showing the main configuration of the liquid chromatograph detector, which differs from FIG. 1 in that an opening member 106 is provided on the rear side of the flow cell 103. In the case of the configuration shown in FIG. 1, the light intensity is limited before the light enters the flow cell 103, but in the configuration shown in FIG. 2, the light enters the flow cell 103 with no limit on the light intensity. As a result, more information can be obtained.

  FIG. 3 is a configuration diagram showing the main configuration of the liquid chromatograph detector. Compared to FIG. 2, the aperture member 106 is provided between the detection-side condensing optical device 104 and the optical sensor 105. Is different.

  FIG. 4 is a configuration diagram showing the main configuration of the liquid chromatograph detector, and shows a moving device and a control device that automatically move the opening member 106 in the optical axis direction. In the control device 401, a processor (not shown) receives light intensity data detected by the optical sensor 105, and transmits a command to operate the motor 403 of the mobile device by executing a preset program. Upon receiving the command, the motor 403 rotates, and the opening member 106 mounted on the stage 402 moves in the optical axis direction.

  FIG. 5 is a configuration diagram showing the configuration of the opening member moving device. An opening member 106 is mounted on the stage 402 so as to be movable in the optical axis direction, and a motor 403 and a rotation shaft 404 are provided. A male screw of the rotation shaft is combined with a female screw of the opening member 106. The moving direction of the opening member 106 is determined by the rotating direction of the rotating shaft 404.

  FIG. 6 is a flowchart showing a procedure for adjusting the position of the opening member, and is executed by the control device 401 shown in FIG. Since the optical sensor 105 cannot detect a level whose light intensity is higher than the saturation level, a light intensity value A close to the saturation level and a light intensity value B slightly lower than the saturation level are determined in advance and detected by the optical sensor 105. The position of the aperture member 106 is controlled so that the light intensity is between the value A and the value B. Thereby, it is possible to detect transmitted light having a high light intensity without exceeding the saturation level of the optical sensor 105.

  First, the light intensity detected by the optical sensor 105 is read (step 601), and the light intensity is compared with the value B (step 602). When the light intensity is greater than value B, it is then compared with value A (step 603). If the light intensity is smaller than the value A, it can be seen that the light intensity is between the value A and the value B, so the position of the opening member 106 is not adjusted.

  If the light intensity value is smaller than the value B in step 602, it is necessary to increase the light intensity. Therefore, the control device 401 issues a command to the motor 403 (step 604), and the opening member 106 increases the light intensity. Move in the direction you want. Then, the light intensity detected by the optical sensor 105 in step 601 is read again, and the steps are repeated until the value is between the value A and the value B. How much the light intensity is increased is set smaller than the difference between the value A and the value B so that the repetition of the steps does not diverge.

  If the light intensity value is larger than the value A in step 603, it is necessary to decrease the light intensity. Therefore, the control device 401 issues a command to the motor 403 (step 605), and the opening member 106 decreases the light intensity. Move in the direction you want. Then, the light intensity detected by the optical sensor 105 in step 601 is read again, and the steps are repeated until the value is between the value A and the value B. The amount of light intensity to be weakened is determined in advance so as to be smaller than the difference between the value A and the value B so that the repetition of steps does not diverge.

  With the technology described in the above embodiments, the light sensor can detect light with a high light intensity level without saturating the light sensor even if there are variations in the manufacture and assembly of light sources and optical components. It is possible to provide a high-performance liquid chromatograph detector.

DESCRIPTION OF SYMBOLS 101 Light source 102 Incident side condensing optical apparatus 103 Flow cell 104 Detection side condensing optical apparatus 105 Optical sensor 106 Opening member 107 Moving apparatus 401 Control apparatus 402 Stage 403 Motor 404 Rotating shaft

Claims (4)

A flow cell for flowing a sample sent from a separation column of a liquid chromatograph;
A light source for causing light to enter the flow cell;
A first condensing optical device that condenses the light emitted from the light source and transmitted through the flow cell;
A second condensing optical device for condensing the light transmitted through the flow cell;
An optical sensor for detecting the light collected by the second condensing optical device ;
Provided from the first focusing optical system until the optical sensor, and an opening member having an opening for passing the light,
A moving device that moves the opening member in the optical axis direction of the light;
A liquid chromatograph detector comprising: a control device that sends a command to move the opening member in the optical axis direction based on the light intensity of the light detected by the optical sensor. In the description of claim 1,
The liquid chromatograph detector, wherein the control device sends the command so that the light intensity of the light detected by the light sensor is lower than a saturation level of the light sensor. In the description of claim 2,
The controller is
A liquid chromatograph detector, wherein the command is sent so that the light intensity of the light detected by the light sensor is increased. In the description of claim 1,
The controller is
The liquid chromatograph is characterized by holding two values lower than a saturation level of the photosensor and sending the command so that the light intensity of the light detected by the photosensor is between the two values. Graph detector.

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