Detector for liquid chromatograph

Abstract

To easily confirm whether air bubbles and dust remain in a flow cell or not.SOLUTION: A flow cytometer includes a flow cell (2) having an internal space (3; 3a; 3b) through which a liquid passes, a light irradiator (4) including a light source (20) and configured to irradiate light emitted from the light source (20) toward the flow cell (2), a light receiver (8) configured to receive measurement light emitted from the flow cell (2), a camera (16) configured to capture an image of the internal space (3; 3a; 3b) of the flow cell (2), and a controller configured to control an operation of the camera (16) to cause the camera (16) to capture the image of the internal space (3; 3a; 3b) of the flow cell (2).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a detector for a liquid chromatograph. [Background technology]

[0002] There are various types of detectors for liquid chromatography, including fluorescence detectors, absorptiometry detectors, differential refractive index detectors, etc. All of these detectors are equipped with a flow cell, and detect and quantify components in the sample liquid by irradiating the flow cell with light while a sample liquid is passed through the internal space of the flow cell and measuring the intensity of the light emitted from the flow cell or the change in the optical path length of the light emitted from the flow cell (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2023-064637 Summary of the Invention [Problem to be solved by the invention]

[0004] Air bubbles and debris may remain inside the flow cell. If analysis is performed with air bubbles or debris inside the flow cell, the baseline of the detector signal may become unstable, which may adversely affect analytical accuracy. For this reason, solvent is passed through the flow cell before starting analysis to expel air bubbles and debris from the flow cell, but air bubbles and debris may still remain even after such processing.

[0005] To date, methods used to check for the presence of air bubbles or debris inside the flow cell include removing the flow cell from the detector and checking visually (only if the flow cell is replaceable), observing the baseline of the detector signal to check the magnitude of drift, and actually analyzing known components to check whether the expected analysis results are being obtained. However, all of these methods impose a workload on the user, and are not easy for the user to use.

[0006] The present invention has been made in view of the above problems, and aims to make it possible to easily check whether air bubbles or dust remain inside a flow cell. [Means for solving the problem]

[0007] The liquid chromatograph detector of the present invention comprises a flow cell having an internal space through which a liquid is passed, a light irradiation unit including a light source and configured to irradiate light emitted by the light source toward the flow cell, a light receiving unit for receiving measurement light emitted from the flow cell, a camera for photographing the internal space of the flow cell, and a control unit configured to control the operation of the camera to cause the camera to photograph the internal space of the flow cell. [Effects of the Invention]

[0008] The liquid chromatograph detector according to the present invention is provided with a camera for photographing the internal space of the flow cell, so that an image of the internal space of the flow cell can be obtained and it can be easily confirmed whether or not bubbles or dust particles are present in the internal space of the flow cell. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram showing an embodiment of a detector for a liquid chromatograph. [Figure 2] FIG. 10 is a diagram illustrating another example of the arrangement position of the camera. [Figure 3] FIG. 10 is a diagram showing an embodiment in which a shutter is provided to prevent stray light. [Figure 4] FIG. 10 is a diagram showing an example of the arrangement position of a camera when the liquid chromatograph detector is a differential refractive index detector. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of a liquid chromatograph detector will be described with reference to the drawings.

[0011] An embodiment of a liquid chromatographic detector is shown in FIG.

[0012] The detector 1 includes a flow cell 2, a light irradiating unit 4, a diffraction grating 6, a measurement light receiving unit 8, a light collecting mirror 10, a half mirror 12, a reference light receiving unit 14, a camera 16, and a control unit 18.

[0013] Flow cell 2 is made of a light-transmitting material and has an internal space 3 through which the sample liquid passes. Light irradiation unit 4 includes a light source 20 and a diffraction grating 22. Light from light source 20 is split by diffraction grating 22, and light of wavelength components that become excitation light for exciting components in the sample liquid is irradiated onto flow cell 2. Diffraction grating 22 is rotated by a drive unit including motor 24, so that the wavelength of light irradiated onto flow cell 2 can be selectively changed.

[0014] The diffraction grating 6 separates the light emitted from the flow cell 2, and causes the fluorescent components emitted from components excited by the excitation light in the flow cell 2 to enter the measurement light receiving unit 8 as measurement light. The measurement light receiving unit 8 detects the intensity of the fluorescence guided from the diffraction grating 6, and is, for example, a photodiode.

[0015] The front surface of the collecting mirror 10 faces the flow cell 2, and the light emitted from the flow cell 2 is reflected by the front surface and directed to the diffraction grating 6. A camera 16 is disposed on the rear side of the collecting mirror 10, i.e., on the opposite side of the collecting mirror 10 from the flow cell 2. A pinhole 11 is provided in the center of the collecting mirror 10, and the camera 16 is able to photograph the internal space 3 of the flow cell 2 through the pinhole 11.

[0016] The half mirror 12 is disposed on the optical axis of the light traveling from the diffraction grating 22 to the flow cell 2, and extracts a portion of the light from the light irradiator 4 as reference light and makes it incident on the reference light receiver 14. The reference light receiver 14 detects the intensity of the reference light from the half mirror 12, and is, for example, a photodiode.

[0017] The control unit 18 controls the operation of the light irradiation unit 4 and the camera 16, and has the function of causing the camera 16 to photograph the internal space 3 of the flow cell 2 based on instructions from the user or at a predetermined timing, such as before the analysis begins.

[0018] When photographing the internal space 3 of the flow cell 2 with the camera 16, the control unit 18 can use the light from the light irradiating unit 4 as illumination for the photograph. Alternatively, a light source for photographing may be provided separately from the light irradiating unit 4, and the control unit 18 may turn on the light source when photographing with the camera 16. When the light from the light irradiating unit 4 is used as illumination for photographing, the light irradiated from the light irradiating unit 4 to the flow cell 2 is not particularly limited as long as it illuminates the internal space 3. However, by irradiating the flow cell 2 with zero-order diffracted light from the diffraction grating 22, the flow cell 2 can be illuminated most brightly, and a clear image or video can be acquired by the camera 16.

[0019] The control unit 18 takes in an image or video of the internal space 3 of the flow cell 2 acquired by the camera 16, and the control unit 18 outputs the image or video to the arithmetic processing device 100, which is connected to the detector 1 so as to be able to communicate with each other. A display 200 is connected to the arithmetic processing device 100 so as to be able to communicate with each other, and the image or video of the internal space 3 of the flow cell 2 acquired by the camera 16 is displayed on the display 200. This allows the user to easily check whether or not there are any bubbles or debris in the internal space 3 of the flow cell 2.

[0020] It is not essential that the image or video captured by the camera 16 be displayed on the display 200. The control unit 18 or the arithmetic processing device 100 may automatically recognize whether or not air bubbles or debris are present in the internal space 3 of the flow cell 2 from the image or video captured by the camera 16, and may take measures such as issuing a warning if air bubbles or debris are present in the internal space 3 of the flow cell 2.

[0021] Here, the control unit 18 can be realized by, for example, an electronic circuit board equipped with a CPU (Central Processing Unit) and an information storage device. The arithmetic processing device 100 can be realized by a computer device such as a personal computer.

[0022] During measurement, the control unit 18 also captures the fluorescence intensity detected by the measurement light-receiving unit 8 and the reference light intensity detected by the reference light-receiving unit 8 at regular intervals, and outputs signals corresponding to the fluorescence intensity and the reference light intensity to the arithmetic processing device 100. The arithmetic processing device 100 detects and quantifies components in the sample liquid flowing through the internal space 3 of the flow cell 2 using the signals corresponding to the fluorescence intensity and the reference light intensity from the control unit 18.

[0023] Since the detector 1 in this embodiment is a fluorescence detector in which the focusing lens 10 is arranged near the flow cell 2, by providing a pinhole 11 in the focusing lens 10, it is possible to arrange the camera 16 behind the focusing lens 10, thereby preventing light reflected by the camera 16 during analysis from becoming stray light and entering the light receiving unit 8 and / or 14.

[0024] On the other hand, the present invention is not limited to detectors having the above-described configuration, and can be applied to various detectors other than fluorescence detectors. As shown in Fig. 2, the camera 16 may be positioned at any position as long as it can capture an image of the internal space 3 of the flow cell 2 and does not affect the analysis. If stray light is generated due to light reflection from the camera 16, as shown in Fig. 3, a shutter 26 that opens and closes in front of the camera 16 may be provided, and the shutter 26 may be closed to block the view in front of the camera 16 during analysis, and opened when the camera 16 is capturing an image of the internal space 3 of the flow cell 2.

[0025] Furthermore, when the present invention is applied to a differential refractive index detector, as shown in FIG. 4, the flow cell 2' has a structure in which an internal space 3a through which a sample liquid flows and an internal space 3b through which a reference liquid flows are arranged with a transparent partition between them. In this case, as shown in the same figure, it is desirable that the camera 16 be positioned so that it can simultaneously photograph both the internal spaces 3a and 3b. However, the present invention is not limited to this. Separate cameras may be provided for photographing the internal space 3a of the flow cell 2' and the internal space 3b, or a single camera may be moved to photograph both the internal spaces 3a and 3b.

[0026] The above-described examples are merely examples of embodiments of the liquid chromatograph detector according to the present invention. The liquid chromatograph detector according to the present invention may be embodied as follows.

[0027] One embodiment of the liquid chromatograph detector according to the present invention comprises a flow cell having an internal space through which a liquid is passed, a light irradiating unit including a light source and configured to irradiate light emitted by the light source toward the flow cell, a light receiving unit for receiving measurement light emitted from the flow cell, a camera for photographing the internal space of the flow cell, and a control unit configured to control the operation of the camera to cause the camera to photograph the internal space of the flow cell.

[0028] In a first aspect of the above embodiment, the apparatus further includes an optical element having a front surface and a rear surface, the optical element being disposed near the flow cell with the front surface facing the flow cell, the optical element having a pinhole extending from the front surface to the rear surface, and the camera being disposed on the opposite side of the optical element from the flow cell so as to capture an image of the internal space of the flow cell through the pinhole. According to this first aspect, the camera is hidden behind the optical element, thereby suppressing stray light caused by reflection from the camera during analysis.

[0029] In the first aspect, the optical element may be a condenser lens for condensing light emitted from the flow cell.

[0030] In a second aspect of the above embodiment, the control unit is configured to control the light irradiating unit to capture an image of the internal space of the flow cell while the light irradiating unit irradiates the flow cell with light. According to this second aspect, there is no need to provide a dedicated light source for capturing an image of the flow cell with a camera. This second aspect can be combined with the first aspect.

[0031] In one preferred embodiment of the second aspect, the light irradiating unit includes a diffraction grating that disperses light from the light source and a drive unit that rotates the diffraction grating to direct light of a desired wavelength toward the flow cell, and the control unit is configured to capture an image of the internal space of the flow cell while irradiating the flow cell with zero-order diffracted light from the diffraction grating. With this embodiment, strong light can be irradiated from the light irradiating unit when photographing the flow cell with a camera, allowing a clear image or video of the internal space of the flow cell to be acquired by the camera.

[0032] In a third aspect of the above embodiment, the control unit is configured to output an image or video of the internal space of the flow cell acquired by the camera to a display connected to the liquid chromatograph detector so as to be able to communicate with the liquid chromatograph detector. According to this third aspect, the image or video of the internal space of the flow cell is displayed on the display, allowing a user to easily check whether or not air bubbles or dust particles are present in the internal space of the flow cell. [Explanation of symbols]

[0033] 1 Liquid chromatograph detector 2,2' flow cell 3,3a,3b Internal space 4. Light irradiation unit 6,22 Diffraction grating 8 Light receiving section for measurement 10 Condenser lens 12 Half mirror 14 Reference light receiving section 16 Camera 18 Control Unit 20 light source 24 motor 26 Shutter 100 Processing unit 200 displays

Claims

1. a flow cell having an internal space through which a liquid passes; a light irradiation unit including a light source and configured to irradiate light emitted by the light source toward the flow cell; a light receiving unit for receiving measurement light emitted from the flow cell; a camera for photographing the internal space of the flow cell; a control unit configured to control the operation of the camera to cause the camera to take an image of the internal space of the flow cell.

2. an optical element having a front surface and a rear surface, the optical element being disposed adjacent to the flow cell with the front surface facing the flow cell; the optical element is provided with a pinhole extending from the front surface to the rear surface, 2. The liquid chromatograph detector according to claim 1, wherein the camera is arranged to capture an image of the internal space of the flow cell through the pinhole from a position opposite the flow cell across the optical element.

3. 3. The liquid chromatograph detector according to claim 2, wherein the optical element is a condenser lens for condensing the light emitted from the flow cell.

4. 2. The liquid chromatograph detector according to claim 1, wherein the control unit is configured to control the light irradiating unit to capture an image of the internal space of the flow cell while the light irradiating unit irradiates the flow cell with light.

5. the light irradiation unit includes a diffraction grating that separates the light from the light source, and a drive unit that rotates the diffraction grating to direct light of a desired wavelength toward the flow cell; 5. The liquid chromatograph detector according to claim 4, wherein the control unit is configured to capture an image of the internal space of the flow cell while irradiating the flow cell with zero-order diffracted light from the diffraction grating.

6. 2. The liquid chromatograph detector according to claim 1, wherein the control unit is configured to output an image or video of the internal space of the flow cell acquired by the camera to a display communicatively connected to the liquid chromatograph detector.

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