WO2013140617A1

WO2013140617A1 - Detector and liquid chromatograph provided with detector

Info

Publication number: WO2013140617A1
Application number: PCT/JP2012/057582
Authority: WO
Inventors: 小田　竜太郎
Original assignee: 株式会社島津製作所
Priority date: 2012-03-23
Filing date: 2012-03-23
Publication date: 2013-09-26

Abstract

A shutter (16) (light blocking shutter) for blocking light from a light source (2), and a shutter drive mechanism (18) for moving the shutter (16) between a position on the optical path of the light emitted from the light source (2) and between the light source (2) and a light collection mirror (4) and a position out of the optical path are provided. A detector control unit (20) is provided with a light irradiation control means (22) for controlling the lighting of the light source (2) and the drive of the shutter by the shutter drive mechanism (18). The light irradiation control means (22) is configured to open the shutter (16) only when the absorbance of a sample is measured.

Description

Detector and liquid chromatograph equipped with the detector

The present invention relates to a detector used for detecting a sample component separated by an analysis column in a liquid chromatograph and a liquid chromatograph provided with the detector.

A spectrophotometer such as a multi-channel absorbance detector is often used as a detector used to detect sample components separated in an analysis column in a liquid chromatograph (see Patent Document 1).

FIG. 22 schematically shows the configuration of a multi-channel absorbance detector.
The detector includes a light source 2 that emits measurement light, a flow cell 6 for flowing an eluate from an analysis column of a liquid chromatograph, a light detector 14 for detecting light, and light from the light source 2 to the flow cell 6. In addition, an optical system for guiding the light transmitted through the flow cell 6 to the photodetector 14 is provided. The optical system includes a mirror 4, a mirror 8, and a concave diffraction grating 12.

The mirror 4 is disposed on the optical axis of the light emitted from the light source 2, and the flow cell 6 is disposed on the optical axis of the light reflected by the mirror 4. A mirror 8 is arranged on the optical axis of the light transmitted through the flow cell 6, and a slit 10 and a concave diffraction grating 12 are arranged at a position on the optical axis of the light reflected by the mirror 8, and are split by the concave diffraction grating 12. The light detector 14 is disposed at a position where the received light can be received. That is, the light from the light source 2 is reflected by the mirror 4 and condensed on the flow cell 6, the light transmitted through the flow cell 6 is reflected by the mirror 8 and condensed on the slit 10, and the light passing through the slit 10 is concavely diffracted. The light is split by the grating 12 and imaged on the photodetector 14. The light source 2 is, for example, a deuterium lamp, and the photodetector 14 is a multichannel photodetector such as a photodiode array.

The photodetector 14 detects a temporal change in the intensity of light for each predetermined wavelength range that has passed through the flow cell 6, and the detection signal is converted as a change in absorbance and sent to an arithmetic control device (not shown). Analysis data processing is performed. Absorbance data obtained from the data processing can be used to obtain an absorption spectrum for the qualification of the sample, or to quantify a specific component based on the relationship between the absorbance at a wavelength where the specific component is absorbed and the sample concentration. it can.

JP 2008-70274 A

In the conventional detector as shown in FIG. 22, since light before being split is incident on the flow cell 6, light having a stronger energy than the split light is incident on the flow cell 6. When the analysis for a certain sample is completed, the mobile phase liquid feeding is stopped until the next analysis is started. On the other hand, since it takes time for the light source of the detector to stabilize after the light is turned on, the light source remains on even after the analysis of a certain sample is completed and the liquid feeding of the mobile phase is stopped. There are many cases. Therefore, light is continuously irradiated from the light source to the flow cell even when the sample is not analyzed.

Parts such as lenses and window plates are provided in the light passage part of the flow cell 6. In an absorbance detector for a liquid chromatograph, ultraviolet light and visible light are often used. Therefore, a material that is transparent to ultraviolet light and visible light is used as a material for components such as lenses and window plates provided in the flow cell 6. Quartz glass is often used. In addition, the mirror 4, mirror 8, and diffraction grating 12 other than the flow cell are often made of aluminum as a reflective material. If light with strong energy continues to pass through these parts, the deterioration of these parts may progress and the light transmittance may decrease. When the performance of these components deteriorates, the amount of light transmitted through the flow cell 6 decreases, and as a result, the intensity of light incident on the photodetector 14 decreases and the ratio of noise increases. As a result, the analysis accuracy of the liquid chromatograph is lowered, which affects high sensitivity analysis.

Therefore, an object of the present invention is to suppress deterioration of components and other optical elements constituting the flow cell.

A first embodiment of a detector according to the present invention includes a light source that emits measurement light, a light detector for detecting light, a flow cell for flowing a sample to be measured, light from the light source to the flow cell, and a flow cell. An optical system for guiding the transmitted light to the photodetector, a shutter mechanism capable of blocking the light from the light source to the flow cell by arranging a light blocking shutter on the optical path of the light guided from the light source to the flow cell, and the sample A light irradiation control means for controlling the operation of the shutter mechanism so that the light shielding shutter is removed from the optical path only when the measurement is performed and the light shielding shutter is disposed on the optical path except when the measurement of the sample is performed. , With.

A second embodiment of the detector according to the present invention includes a light source for emitting measurement light, a flow cell for flowing a sample to be measured, an optical system for guiding light from the light source to the flow cell, and light detection for detecting light. And at least a part of the light in the wavelength range not used for measurement from the light irradiated to the flow cell when placed on the optical path of the light guided from the light source to the flow cell when the measurement of the sample is executed Or a neutral density filter having a light shielding characteristic.

The liquid chromatograph according to the present invention includes an analysis channel, a sample introduction unit for introducing a sample into the analysis channel, a mobile phase solution feeding unit for feeding a mobile phase in the analysis channel, An analysis column is provided on the downstream side of the sample introduction section on the analysis flow path, and is separated from the sample introduced by the sample introduction section for each component, and is provided on the analysis flow path on the downstream side of the analysis column. And a detector for detecting the separated sample component, wherein the detector includes the first form or the second form of the detector according to the present invention.

In the first embodiment of the detector according to the present invention, a shutter mechanism that can block the light from the light source to the flow cell by arranging a light blocking shutter on the optical path of the light guided from the light source to the flow cell, and the measurement of the sample A light irradiation control means for controlling the shutter mechanism so that the light shielding shutter is removed from the optical path only when it is executed, and the light shielding shutter is arranged on the optical path except when the measurement of the sample is executed. Therefore, when the measurement of the sample is not executed, the light from the light source is blocked by the light blocking shutter and does not pass through the flow cell. Thereby, the time for the light from the light source to pass through the flow cell can be shortened, and the progress of deterioration of components such as lenses and other optical elements constituting the flow cell can be suppressed.

In the second embodiment of the detector of the present invention, at least a part of light in a wavelength range not used for measurement is dimmed or shielded from the light irradiated to the flow cell, which is disposed on the optical path of the light guided from the light source to the flow cell. Because it is equipped with a neutral density filter, it is possible to reduce the intensity of the light irradiated to the flow cell at least during sample measurement, and the deterioration of parts such as lenses and other optical elements that constitute the flow cell. Can be suppressed.

In the liquid chromatograph of the present invention provided with the first or second detector, the progress of deterioration of components such as lenses and other optical elements constituting the flow cell of the detector is suppressed, so that the reliability of the analysis is improved. Deterioration can be suppressed.

Moreover, the second embodiment of the detector according to the present invention and the liquid chromatograph provided with the second embodiment also provide an effect that the following problems can be improved.
First, when measuring a sample, light with strong energy is irradiated to the flow cell, and the sample in the flow cell is altered. Especially, the low-concentration sample is greatly affected by alteration due to light irradiation, and the relationship between concentration and absorbance. There is a problem that the linearity of the sample deteriorates and the accuracy of quantification deteriorates.

FIG. 15 is a graph showing an absorbance spectrum for each elapsed time from the start of light irradiation measured by sealing the anti-inflammatory analgesic as a sample in the flow cell after stopping the liquid feeding to the flow cell. FIG. 16 is a graph showing the temporal change in absorbance at a measurement wavelength of 260 nm in the data of FIG. In FIG. 15, the absorbance spectrum at the start of light irradiation can be referred to as the original absorbance spectrum of the sample. The absorbance spectrum changes with the passage of time from the start of light irradiation, and the absorbance at a wavelength of 260 nm increases with the passage of time. Yes. In the liquid chromatograph, the sample is irradiated with light while passing through the flow cell, but the sample is altered within the passage time, and the influence becomes greater as the concentration is lower. In this example, the linearity at a wavelength of 260 nm deteriorates as shown by the graph in FIG. Further, in contrast to the examples of FIGS. 15 and 16, the light absorbance may decrease due to light irradiation, in which case the linearity deteriorates as shown in FIG. 17B. The reason why the linearity of absorbance deteriorates as the sample concentration decreases is that the amount of light received per molecule increases as the sample concentration decreases, so the proportion of denatured molecules increases and changes from the original absorbance. It is thought that it is from.

In addition, if the sample of the flow cell is irradiated with light other than the wavelength used for measuring the absorbance, and the sample contains a component that emits fluorescence when excited by light of such wavelength, the fluorescence emitted from that component If the wavelength range used for the measurement of absorbance is included in this wavelength range, the linearity of the relationship between concentration and absorbance deteriorates due to the influence of the fluorescence, and there is also a problem that the accuracy of quantification deteriorates. For example, in the measurement of a sample having an absorption spectrum as shown in FIG. 15, when the sample is quantified by measuring the absorbance at 260 nm, a component that is excited by light having a wavelength near 210 nm and emits fluorescence having a wavelength near 260 nm is used. In this case, the fluorescence emitted from the sample is also measured by the photodetector, and the measured value is used for measuring the absorbance. Therefore, the linearity between the sample concentration and the measured absorbance deteriorates, and the quantification The accuracy of will deteriorate.

The above problems can be improved or solved by removing components not used for measurement from the light irradiated to the flow cell by the neutral density filter. The problem of deterioration of the sample due to the energy of the irradiated light can be improved by reducing the energy of the light irradiated to the flow cell by dimming or blocking a part of the light having a wavelength not used for measurement by the neutral density filter. The problem of fluorescence emitted from components contained in the sample can be solved by removing the wavelength components that excite such components with a neutral density filter.

It is a block diagram which shows roughly one Example of a detector. It is a figure which shows roughly an example of the shutter drive mechanism of the Example. It is a schematic block diagram which shows one Example of a liquid chromatograph. It is a schematic block diagram which shows the other Example of a liquid chromatograph. It is a flowchart for demonstrating an example of the shutter opening / closing operation | movement of the Example of FIG. It is a flowchart for demonstrating the other example of the shutter opening / closing operation | movement of the Example of FIG. 6 is a flowchart for explaining still another example of the shutter opening / closing operation of the embodiment of FIG. 1. 6 is a flowchart for explaining still another example of the shutter opening / closing operation of the embodiment of FIG. 1. It is a flowchart for demonstrating operation | movement of the Example of FIG. It is a flowchart for demonstrating operation | movement of the Example of FIG. It is a figure which shows an example of the structure of a flow cell. It is a block diagram which shows schematically the other Example of a detector. It is a schematic block diagram which shows the further another Example of a liquid chromatograph. It is a block diagram which shows schematically the other Example of a detector. It is a graph which shows the absorption spectrum for every elapsed time from the time of the light irradiation start measured by stopping liquid feeding to a flow cell, and enclosing an anti-inflammatory analgesic in the flow cell. It is a graph which shows the time change of the light absorbency in the measurement wavelength of 260 nm in the data of FIG. It is a figure for demonstrating the influence which the alteration of the sample by the light irradiated to a sample has on the linearity of a light absorbency. It is a block diagram which shows schematically the further another Example of a detector. It is a figure which shows an example of a shutter and a filter drive mechanism roughly. It is a figure which shows an example of the wavelength characteristic of a neutral density filter. It is a figure which shows an example of the flow cell which attached the neutral density filter. It is a block diagram which shows an example of the conventional detector roughly.

DESCRIPTION OF SYMBOLS 1 Detector 2

Light source

4, 8, 40, 44, 50 Mirror 6 Flow cell 10

Slit

12, 48 Diffraction grating (spectral element)
14 Photodiode array (photodetector)
DESCRIPTION OF SYMBOLS 16 Shutter 18 Shutter drive mechanism 20 Detector control part 22 Light irradiation control means 23 Computation control apparatus 24 Analysis flow path 26 Liquid feed pump 28 Mobile phase 30 Sample injection part 32 Analysis column 52 Beam splitter 54 Sample side photodetector 56 Reference side Photodetector 60 Neutral filter 62 Shutter and filter drive mechanism

As an optical system for guiding light from the light source to the flow cell, a condensing mirror for condensing the light from the light source and guiding it to the flow cell may be provided between the light source and the flow cell. If such a condensing mirror is continuously irradiated with light having strong energy, the deterioration proceeds like the lens of the flow cell and the like, resulting in a problem that the reflectance decreases.

Therefore, in the first embodiment of the detector of the present invention, the shutter mechanism may be configured to shield the light from the light source to the flow cell by arranging a light shielding shutter between the light source and the condenser mirror. Then, when the analysis of the sample is not performed, the light from the light source is not irradiated to the condenser mirror, and the irradiation time of the light to the condenser mirror is reduced and the deterioration of the condenser mirror is progressed. Can be suppressed.

Similarly, in the second embodiment of the detector of the present invention, if the neutral density filter is arranged between the light source and the collector mirror, the energy of the light irradiated to the collector mirror can be reduced. It is possible to suppress the progress of deterioration of the condenser mirror.

The first and second embodiments of the detector according to the present invention include those in which the optical system has a configuration for guiding the light transmitted through the flow cell to the photodetector. For example, in a spectrophotometer, the light from the light source is dispersed with a spectroscope, the dispersed light is guided to the flow cell, and the transmitted light is detected with a detector provided immediately after the flow cell. There is a post-spectrometry method in which the light is guided to the flow cell for irradiation, the light transmitted through the flow cell is guided to the spectroscope for spectroscopy, and the dispersed light is detected by the detector. In the pre-spectroscopy method, no optical system exists between the flow cell and the detector, and in the post-spectroscopy method, an optical system exists between the flow cell and the detector. The detector of the present invention includes both of these types.

In the first embodiment of the detector of the present invention, at least when the measurement of the sample is performed, the detector is disposed on the optical path of the light guided from the light source to the flow cell, and the light irradiated to the flow cell is used in a wavelength region that is not used for the measurement. You may further provide the neutral density filter which has the characteristic to reduce or block at least one part of certain light. By doing so, it is possible to suppress the progress of deterioration of parts such as a lens constituting the flow cell and other optical elements by the light shielding shutter, and to reduce the energy of the light irradiated to the sample at the time of measurement. Can be suppressed.

As a preferred embodiment of the above case, the optical system further includes a filter driving mechanism that performs an operation of disposing the neutral density filter on the optical path and an operation of removing the neutral density filter from the optical path, and the filter driving mechanism is a sample having a property of being altered at least by light irradiation. In this measurement, a neutral density filter is arranged on the optical path. As a result, it is possible to prevent the sample from being altered during the analysis of the sample that is altered by light irradiation, and to remove the neutral density filter from the optical path and use it for the analysis of the sample that is not altered by the light irradiation. It is also possible to perform high sensitivity analysis without attenuating the amount of light.

As a preferred embodiment of the second form of the detector of the present invention, the detector further includes a filter driving mechanism that performs an operation of disposing the neutral density filter on the optical path and an operation of removing it from the optical path, and the filter driving mechanism is at least by light irradiation Examples include a filter in which an attenuating filter is arranged on an optical path when measuring a sample having a property of changing quality. As a result, it is possible to prevent the sample from being altered during the analysis of the sample that is altered by light irradiation, and to remove the neutral density filter from the optical path and use it for the analysis of the sample that is not altered by the light irradiation. It is also possible to perform high sensitivity analysis without attenuating the amount of light.

As an example of a preferred embodiment of a liquid chromatograph equipped with the first embodiment of the detector of the present invention, a sample introduction unit, a mobile phase liquid feeding unit, and a control unit that controls the operation by transmitting a control signal to the detector When the light irradiation control means of the detector receives a signal for starting the analysis of the sample from the control unit, the light shielding shutter is removed from the optical path of the light from the light source, and the sample is analyzed from the control unit. For example, there is a configuration in which a light-shielding shutter is arranged on the optical path when a signal for ending is received.

Further, as another example of the preferred embodiment of the liquid chromatograph provided with the first form of the detector of the present invention, the operation is performed by transmitting a control signal to the sample introduction part, the mobile phase liquid feeding part and the detector. The light irradiation control means of the detector further removes the light-shielding shutter from the light path of the light from the light source and receives the analysis when receiving a signal for starting the analysis of the sample from the control unit. The time elapsed since the start of the measurement is counted, and when the time required for the analysis has elapsed since the start of the analysis, a light shielding shutter is arranged on the optical path.

As still another example of the preferred embodiment of the liquid chromatograph including the first form of the detector of the present invention, the mobile phase liquid feeding unit is feeding the mobile phase while feeding the mobile phase. While the light irradiation control means of the detector is receiving a signal indicating that the mobile phase is being fed from the mobile phase liquid feeding unit, The light-shielding shutter is removed from the light path of the light from the light source, and the light-shielding shutter is arranged on the light path when the mobile phase liquid feeding unit stops receiving a signal indicating that the mobile phase is being fed. What is being done is mentioned.

In the liquid chromatograph provided with the first embodiment of the detector of the present invention, an arithmetic processing unit that performs arithmetic processing on a sample based on a detection signal obtained by the detector, and a light shielding shutter of the detector are provided on the optical path. And a dark current data holding unit that holds a dark current value of a light detector element measured in a state of being arranged in the detector, and the arithmetic processing unit is a detector for measuring the sample in the arithmetic processing for the sample. The dark current value held in the dark current data holding unit may be subtracted from the detection signal obtained in the above and used for the arithmetic processing.

Hereinafter, an embodiment of a detector and a liquid chromatograph of the present invention will be described with reference to the drawings. First, an embodiment of the detector will be described with reference to FIG.
The detector 1 includes a light source 2 that emits measurement light, a flow cell 6 for flowing an eluate from an analysis column of a liquid chromatograph, a light detector 14 for detecting light, and light from the light source 2 to the flow cell 6. An optical system that guides the light transmitted through the flow cell 6 to the photodetector 14 is provided. The optical system includes a mirror 4, a mirror 8, and a concave diffraction grating 12.

An example of the structure of the flow cell 6 is shown in FIG. A cell 36 is formed inside the housing 42. An inlet channel 38 is connected to one end of the cell 36, and an outlet channel 40 is connected to the other end of the cell 36. A lens 44 is disposed on the side of the light incident side of the cell 36 via a gasket 45, and the lens 44 and the gasket 45 are fixed to the housing 42 by a fixing screw 46. A flat window plate 48 is disposed on the side of the light emission side of the cell 36 via a gasket 49, and the window plate 48 and the gasket 49 are fixed to the housing 42 by a fixing screw 50. The lens 44 and the window plate 48 are made of, for example, synthetic quartz glass, and the

gaskets

45 and 49 are made of a fluororesin.

Referring back to FIG. 1, the photodetector 14 detects a temporal change in the intensity of light for each predetermined wavelength range that has passed through the flow cell 6, and the detection signal is converted as a change in absorbance so that the arithmetic control device 23, analysis data processing is performed. Absorbance data obtained from the data processing can be used to obtain an absorption spectrum for the qualification of the sample, or to quantify a specific component based on the relationship between the absorbance at a wavelength where the specific component is absorbed and the sample concentration. it can.

A shutter 16 (light-shielding shutter) for shielding light from the light source 2 and a shutter drive mechanism 18 that can be disposed on or removed from the light path of the light from the light source 2 are provided. In this embodiment, the shutter 16 is arranged on the optical path of the light from the light source 2 between the light source 2 and the condenser mirror 4. The shutter 16 and the shutter drive mechanism 18 constitute a shutter mechanism. Hereinafter, disposing the shutter 16 on the optical path of the light from the light source 2 is expressed as “closing”, and removing the shutter 16 from the optical path is expressed as “opening”.

An example of the shutter drive mechanism 18 is to rotationally drive a shutter 16 that shields light by a motor 18a, as shown in FIG. The position of the shutter 16 is controlled by a motor drive unit 18b that controls the rotation of the motor 18a by applying a voltage to the motor 18a. The configuration of the shutter mechanism is not limited to this, and any configuration may be used as long as the shutter 16 can be opened and closed.

Referring back to FIG. 1, the detector 1 includes a detector control unit 20. The detector control unit 20 is realized by a computer, and controls the light source 2, the shutter drive mechanism 18, and the photodetector 14 based on a control signal given from an external arithmetic control device 23. Further, the detection signal obtained by the photodetector 14 is input to the arithmetic control device 23 via the detector control unit 20, and the arithmetic control device 23 performs an operation for obtaining the absorbance and the like. The arithmetic control device 23 will be described later.

The detector control unit 20 includes light irradiation control means 22 for controlling the lighting of the light source 2 and the driving of the shutter by the shutter driving mechanism 18. The light irradiation control means 22 is configured to open the shutter 16 only when measuring the absorbance of the sample.

As shown in the flowchart of FIG. 5, the light irradiation control means 22 keeps the shutter 16 closed until it receives a sample analysis start signal from the arithmetic and control unit 23, and receives the analysis start signal. The shutter 16 is configured to open. And the detector control part 20 is comprised so that the shutter 16 may be closed again, when the signal of the completion | finish of analysis from the arithmetic control apparatus 23 is received.

The operation of closing the shutter 16 after the analysis is not necessarily performed based on the signal from the arithmetic control device 23 as described above. As shown in the flowchart of FIG. 6, when the detector control unit 20 receives an analysis start signal from the arithmetic control device 23, it also receives information on the time required for analysis, and the detector control unit 20 starts the analysis. The light irradiation control means 22 may be configured so as to measure the time from the time until the shutter 16 is closed when the time required for analysis has elapsed.

When analyzing a plurality of samples continuously, the light irradiation control means 22 of the detector control unit 20 starts a series of analyzes from the arithmetic control device 23 as shown in the flowchart of FIG. The shutter 16 is opened based on this signal, and the shutter 16 is closed based on the end signal of a series of analyzes from the arithmetic and control unit 23.

Note that the operation of closing the shutter 16 after the end of a series of analyzes in the case of analyzing a plurality of samples continuously does not necessarily have to be performed based on the signal from the arithmetic and control unit 23 as described above. As shown in the flowchart of FIG. 8, when the detector control unit 20 receives an analysis start signal from the arithmetic control device 23, it also receives information on the analysis schedule set in the arithmetic control device 23. When starting the analysis, the detector control unit 20 receives information indicating that the analysis is the last analysis and the time required for the analysis from the arithmetic and control unit 23, and the time required after receiving the signal for starting the last analysis. The light irradiation control means 22 may be configured to measure the time until the passage of time and close the shutter 16 when the last analysis is completed.

Next, an example of a liquid chromatograph will be described with reference to FIG.
A liquid feed pump 26 for feeding the mobile phase 28 from the upstream side onto the analysis channel 24, a sample injection part (autosampler) 30 for injecting the sample into the analysis channel 24, and a sample for each component An analysis column 32 and a detector 1 for separation are provided. The arithmetic control device 23 has functions of an arithmetic processing unit and a control unit, and controls the operations of the liquid feed pump 26, the sample injection unit 30, and the detector 1, and based on signals obtained by the detector 1. Calculation to obtain absorbance and the like is performed. The arithmetic and control unit 23 can be realized by, for example, a PC (personal computer) or a dedicated computer, as well as those including those computers and a system controller. The system controller is interposed between a PC or a dedicated computer and each device such as the liquid feed pump 26, the sample injection unit 30, and the detector 1, and sets operations and operating conditions for each of these devices.

An example of the operation of the liquid chromatograph will be briefly described with reference to the flowcharts of FIGS. 1 and 9 together with FIG.
An analysis schedule and analysis conditions are set in the arithmetic and control unit 23. When the operation of the liquid chromatograph is started, an operation start signal is given from the arithmetic and control unit 23 to the detector 1 and the liquid feed pump 26. Upon receiving the operation start signal, the detector 1 closes the shutter 16 and turns on the light source 2. Upon receiving the operation start signal, the liquid feed pump 26 starts to feed the mobile phase. Then, it waits for a fixed time until the emitted light quantity of the light source 2 of the detector 1 is stabilized.

After the standby time until the light emission of the light source 2 is stabilized, an analysis start signal is given from the arithmetic and control unit 23 to the detector 1 and the sample injection unit 30. Upon receiving the analysis start signal, the detector 1 opens the shutter 16 and irradiates the flow cell 6 with light from the light source 2. Upon receiving the analysis start signal, the sample injection unit 30 injects the sample into the analysis flow path 24. The sample injected into the analysis channel 24 is separated for each component in the analysis column 32, and then introduced into the flow cell 6 of the detector 1, whereby the absorbance is measured and the component concentration is quantified.

After the analysis is completed, if the next sample to be measured is in the analysis schedule, the next sample is injected into the analysis flow path 24 by the sample injection unit 30 and analyzed. When the analysis for all the samples in the analysis schedule is completed, the arithmetic and control unit 23 gives an analysis end signal to the detector 1, and the detector 1 receiving the analysis end signal closes the shutter 16 and puts it in the flow cell 6. Blocks the irradiated light.

When there is another analysis schedule, the arithmetic and control unit 23 gives an analysis start signal to the detector 1 and the sample injection unit 30 based on the new analysis schedule, whereby the detector 1 opens the shutter 16 and the sample injection The unit 30 sequentially injects the sample into the analysis channel 24 and executes analysis of the analysis schedule.

When there is no other analysis schedule and the operation of the liquid chromatograph is to be terminated, the arithmetic and control unit 23 gives an operation end signal to the detector 1 and the liquid feed pump 26. Upon receiving the operation end signal, the detector 1 turns off the light source 2 and the liquid feed pump 26 stops the mobile phase liquid feed. Thereby, the operation of the liquid chromatograph is completed.

Note that the detector and the liquid chromatograph of the present invention are not limited to those in which the opening and closing of the shutter 16 of the detector 1 is performed based on the signal from the arithmetic control device 23 and the elapsed time from the start of analysis. For example, as shown in FIG. 13, while the liquid feeding pump 26 is feeding the mobile phase, a signal indicating that the mobile phase is being fed is transmitted to the detector control unit 20 of the detector 1. The detector control unit 20 opens the shutter 16 while receiving a signal from the liquid feeding pump 26, and closes the shutter 16 when no signal is received. Good.

In addition, the advantage that the light incident on the photodetector 14 can be blocked by closing the shutter 16 without turning off the light source 2 makes it possible to provide the apparatus with a function of eliminating the influence of the dark current of the elements of the photodetector 14. It is. The dark current value of each element of the photodetector 14 is determined by measuring the signal of each element of the multi-channel photodetector 14 with the shutter 16 closed and the light incident on the photodetector 14 blocked. Can be measured. The measured value can be corrected using the dark current value.

Specifically, as shown in FIG. 4, a dark current data holding unit 23 a for holding the measured dark current value is provided in the arithmetic control device 23. Then, when calculating the absorbance, as shown in the flowchart of FIG. 10, the detection signal data of each element of the photodetector 14 with respect to the sample with the shutter 16 opened is collected, and the dark current is obtained. The dark current value held in the data holding unit 23a is subtracted from the collected detection signal value, and the calculation for obtaining the absorbance of the sample component is performed using the detection signal data after the dark current value is subtracted. Thereby, the light absorbency which reduced the influence of the dark current of the photodetector 14 can be calculated | required. In the example of FIG. 4, the dark current data holding unit 23 a is provided in the arithmetic control device 23, but the dark current data holding unit 23 a is provided by a data memory or other storage device provided in the detector control unit 20. Can also be realized.

In the embodiment shown in FIG. 1, the shutter 16 is arranged between the light source 2 and the condenser mirror 4 when the shutter 16 is closed, but the present invention is not limited to this. 12, a shutter 16 may be disposed between the mirror 4 and the flow cell 6. In short, even when other optical components are provided, when the shutter 16 is closed, the shutter 16 is disposed at least on the optical path of the light from the light source 2 between the light source 2 and the flow cell 6. Well, by doing so, it is possible to suppress the progress of deterioration of components such as lenses, the mirror 8 and the diffraction grating 12 constituting the flow cell 6. As in the embodiment of FIG. 1, by arranging the shutter 16 closer to the light source 2 than other optical components, it is possible to suppress the progress of deterioration of more optical components such as the condensing mirror 4. it can.

In the embodiment described with reference to FIGS. 1 and 12, the light from the light source 2 is guided to the flow cell 6, and the light transmitted through the flow cell 6 is dispersed by the spectroscope 12 and detected by the photodetector 14. Although it is a spectrophotometer, the detector according to the present invention is not limited to this. The light after the light from the light source is separated by the spectroscope is guided to the flow cell, and the light transmitted through the flow cell is detected by the photodetector. The present invention can also be applied to a pre-spectroscopic spectrophotometer detected by the above method.

FIG. 14 is a schematic configuration diagram showing an embodiment in which the present invention is applied to a pre-spectral spectrophotometer.
The detector 1a of this embodiment includes a mirror 40, a slit 42, a mirror 44, a diffraction grating 46, and a mirror 50 as an optical system for guiding the light from the light source 2 to the flow cell 6. The light from the light source 2 is condensed on the slit 42 by the mirror 40, and the light transmitted through the slit 42 is reflected by the mirror 44 and enters the diffraction grating 46.

The light incident on the diffraction grating 46 is dispersed in the wavelength direction, and the wavelength component used for measuring the absorbance of the sample is guided to the mirror 50. The diffraction grating 46 is rotated about a rotation axis 47 by a diffraction grating rotating mechanism 48. The relationship between the rotation angle of the diffraction grating 46 and the wavelength of the light extracted toward the flow cell 6 is set in advance, and the detector control unit 20a extracts the light of the wavelength used for measurement and irradiates the flow cell 6 with it. As described above, the installation angle is adjusted by rotating the diffraction grating 46. The light split by the diffraction grating 46 and incident on the mirror 50 is reflected by the mirror 50 and applied to the flow cell 6, and the light transmitted through the flow cell 6 is detected by the sample-side photodetector 54 provided immediately after the flow cell 6. The

A beam splitter 52 is installed between the mirror 50 and the flow cell 6. The beam splitter 52 extracts a part of the light traveling from the mirror 50 toward the flow cell 6 and guides it to the reference side photodetector 56, and the reference side photodetector 56 emits a part of the light emitted to the flow cell 6. Measured. The detection signal of the reference-side photodetector 56 is used to correct the influence due to the variation in the amount of light irradiated to the flow cell 6.

The temporal change in the intensity of the light transmitted through the flow cell 6 is detected in the sample-side photodetector 54, and the detection signal is converted as an absorbance change and sent to the arithmetic control device 23a. The arithmetic and control unit 23a obtains the absorbance of the sample flowing through the flow cell 6 based on the detection signals of the sample-side photodetector 54 and the reference-side photodetector 56, and uses a calibration curve representing the relationship between the absorbance and the sample concentration prepared in advance. Based on this, the specific component is quantified.

A shutter 16 is arranged on the optical path of light from the light source 2 toward the mirror 40. The shutter 16 is disposed on the optical path or removed from the optical path by the shutter driving mechanism 18. In addition to the mirror 40, mirror 44, diffraction grating 46 and mirror 50 constituting the optical system of the detector 1a by closing the shutter 16 when the sample is not analyzed while the light source 2 is lit, It is possible to suppress the progress of deterioration of the lens provided in the flow cell 6.

1 and 12, the position where the shutter 16 is disposed is not limited to the position between the light source 2 and the mirror 40, and the light source 2, the flow cell 6, and the like. As long as it is on the optical path of the light from the light source 2 between them, it is possible to suppress the progress of deterioration of components such as optical components and lenses of the flow cell 6 on the rear side of the shutter 16.

Next, an embodiment of the detector of the present invention using a neutral density filter will be described with reference to FIG.
The detector 1b of this embodiment is obtained by adding a neutral density filter (hereinafter referred to as a filter) 60 to the detector 1 of FIG. 1 and changing the shutter driving mechanism 18 to a shutter and filter driving mechanism 62. Other configurations are the same as those of the detector 1 of FIG. 1, and a detailed description thereof is omitted here. A shutter 16 and a filter 60 are arranged on the optical path of light from the light source 2 toward the mirror 4. The shutter 16 and the filter 60 are arranged on the optical path of the light from the light source 2 by the shutter and filter driving mechanism 62 or are removed from the optical path. In this embodiment, the shutter 16 and the filter 60 are driven by a common mechanism called the shutter and filter drive mechanism 62, but may be driven by separate drive mechanisms. .

An example of the configuration of the shutter 16, the filter 60, the shutter, and the filter driving mechanism 62 is shown in FIG. In this example, the filter 60 is provided as a partial region of the shutter 16 and is driven to rotate by a motor 62a. By rotating the motor 62a, the shutter 16 is disposed on the optical path of the light from the light source 2, the filter 60 is disposed on the optical path of the light from the light source 2, and both the shutter 16 and the filter 60 are separated from the light source 2. It is possible to make it not placed on the optical path of the light.

Similar to the embodiment described with reference to FIGS. 1, 12, and 14, when the sample is not analyzed, the shutter 16 is disposed on the optical path of the light from the light source 2, and the optical components constituting the optical system are deteriorated. Is prevented. Further, in this embodiment, when the sample is analyzed, the filter 60 is disposed on the optical path of the light from the light source 2, thereby reducing the energy of the light from the light source 2 at the time of analyzing the sample, and the subsequent stage. The deterioration of the sample in the flow cell 6 due to light irradiation can be suppressed while the deterioration of the optical component on the side can be suppressed. Further, in the case where the sample flowing through the flow cell 6 has a property that does not change due to light irradiation, it is possible to perform high-sensitivity measurement without arranging the filter 60 on the optical path of the light from the light source 2.

As an example of a method for selecting a filter to be used as the filter 60, a case will be described in which a sample having an absorbance spectrum as shown in FIG. 15 is quantified by measuring absorbance at a wavelength of 260 nm.
As shown in the absorbance spectrum of FIG. 15, this sample has strong absorption on the shorter wavelength side than 260 nm used for measurement, and particularly has strong absorption on the shorter wavelength side than 220 nm. Therefore, as the wavelength characteristics of the filter used as the filter 60, it is preferable to use a filter having characteristics that hardly transmit light on the short wavelength side from around 220 nm as shown in FIG. Then, light having a wavelength component that is absorbed by the sample and not used for measurement can be removed by the filter 60, and deterioration of the sample due to light irradiation can be suppressed. Note that a plurality of types of filters used as the filter 60 are prepared, and the filter to be used may be determined according to the characteristics of the sample to be measured.

If the absorbance spectrum of the sample component to be analyzed is known in advance, a filter that transmits light in the vicinity of the wavelength used for measurement within the wavelength range with the absorption and attenuates wavelength components not used for measurement Select. Even if the absorbance spectrum of the sample component to be analyzed is not known, the multi-channel absorbance detector can easily measure the spectrum. Therefore, the absorbance spectrum of the target component is measured without the filter 60 being installed in the optical path. The filter wavelength and transmittance characteristics are selected as in the case where the absorbance spectrum of the target component is known.

In addition, when measuring a sample component that has the same level of absorption for light on both the long wavelength side and the short wavelength side of the wavelength range used for measurement, the wavelength range used for measurement It is preferable to select a filter that attenuates light on the short wavelength side. Since the light on the short wavelength side has stronger energy than the light on the long wavelength side, the wavelength range used for measurement can be selected by selecting a filter that attenuates light on the short wavelength side rather than the wavelength range used for measurement. It is possible to more efficiently suppress the deterioration of the sample component than selecting a filter that attenuates light on the longer wavelength side.

Since the filter having the light transmission characteristics as shown in FIG. 20 has some transmittance even in a short wavelength region of 220 nm or less, the filter is arranged on the optical path using light in the wavelength region in which the filter absorbs. The absorbance spectrum of the sample can be obtained by taking the difference between the absorbance spectrum of the mobile phase and the sample in the state, and the absorbance spectrum of the sample can be accurately measured while suppressing the alteration of the sample.

Further, when the sample is excited by light of a specific wavelength range of 220 nm or less and emits fluorescence, a filter having a light transmission characteristic as shown in FIG. It is possible to suppress the generation of fluorescence that inhibits the absorbance measurement.

In this embodiment, the filter 60 is arranged between the light source 2 and the condenser mirror 4, but the present invention is not limited to this, and between the light source 2 and the flow cell 6. Any position on the optical path of the light irradiated to the flow cell 6 may be used. As in the embodiment of FIG. 18, the filter 60 is arranged at a position closer to the light source 2 than other optical components, thereby suppressing the progress of deterioration of more optical components such as the condenser mirror 4. it can.

In the embodiment of FIG. 18, the filter 60 is driven by a driving mechanism, and is arranged on or removed from the optical path of the light from the light source 2, but the present invention is not limited to this. Instead, the filter 60 may be always arranged on the optical path of the light from the light source 2. In that case, it can be realized by forming the lens 44 of the flow cell 6 of FIG. 11 with the material of the filter 60 of FIG. Thereby, without increasing the number of parts constituting the detector, it is possible to suppress the deterioration of the optical parts on the subsequent stage and the deterioration of the sample. Further, as shown in FIG. 21, the same effect can be obtained even if the filter 60 is attached to the entrance window side of the flow cell 6a.

Claims

A light source that emits measurement light;
A flow cell for flowing a sample to be measured;
An optical system for guiding light from the light source to the flow cell;
A photodetector for detecting light;
A shutter mechanism capable of blocking light from the light source to the flow cell by disposing a light blocking shutter on an optical path of light guided from the light source to the flow cell;
The operation of the shutter mechanism is controlled so that the light shielding shutter is removed from the optical path only when the sample measurement is performed, and the light shielding shutter is disposed on the optical path except when the sample measurement is performed. And a light irradiation control means.
The optical system includes a condensing means for condensing light from the light source between the light source and the flow cell and guiding the light to the flow cell.
2. The detector according to claim 1, wherein the shutter mechanism is configured to shield the light from the light source to the flow cell by disposing the light shielding shutter between the light source and the condensing unit.
A neutral density filter disposed on an optical path of light guided from the light source to the flow cell and having a characteristic of dimming or shielding at least part of light in a wavelength range not used for measurement from the light irradiated on the flow cell; The detector according to claim 1 or 2 further provided.
A filter driving mechanism for performing an operation of disposing the neutral density filter on the optical path and an operation of removing the neutral density filter from the optical path;
The detector according to claim 1, wherein the filter driving mechanism arranges the neutral density filter on the optical path at the time of measuring a sample having a property of being altered at least by light irradiation.
The detector according to any one of claims 1 to 4, wherein the optical system also has a configuration for guiding light transmitted through the flow cell to the photodetector.
A light source that emits measurement light;
A flow cell for flowing a sample to be measured;
An optical system for guiding light from the light source to the flow cell;
A photodetector for detecting light;
At least a part of the light in the wavelength range not used for measurement is dimmed from the light that is arranged on the optical path of light guided from the light source to the flow cell when the measurement of the sample is performed. Or a neutral density filter having a characteristic of shielding light.
A filter driving mechanism for performing an operation of disposing the neutral density filter on the optical path and an operation of removing the neutral density filter from the optical path;
The detector according to claim 6, wherein the filter driving mechanism arranges the neutral density filter on the optical path when measuring at least a sample having a property of being altered by light irradiation.
The optical system includes a condensing means for condensing light from the light source between the light source and the flow cell and guiding the light to the flow cell.
The detector according to claim 6 or 7, wherein the neutral density filter is disposed between the light source and the light collecting means.
The detector according to any one of claims 6 to 8, wherein the optical system also has a configuration for guiding light transmitted through the flow cell to the photodetector.
An analysis channel;
A sample introduction part for introducing a sample into the analysis flow path;
A mobile phase liquid feeding unit for feeding a mobile phase in the analysis flow path;
An analysis column provided on the downstream side of the sample introduction part on the analysis flow path, for separating the sample introduced by the sample introduction part for each component;
A liquid comprising: the detector according to any one of claims 1 to 5, which is provided on the downstream side of the analysis column on the analysis flow path and detects a sample component separated by the analysis column. Chromatograph.
A control unit for controlling the operation by transmitting a control signal to the sample introduction unit, the mobile phase liquid feeding unit, and the detector;
The light irradiation control means of the detector removes the light blocking shutter from the light path of the light from the light source when receiving a signal for starting the analysis of the sample from the control unit, and removes the sample from the control unit. The liquid chromatograph according to claim 10, wherein the light shielding shutter is arranged on the optical path when a signal for ending the analysis is received.
A control unit for controlling the operation by transmitting a control signal to the sample introduction unit, the mobile phase liquid feeding unit, and the detector;
The light irradiation control means of the detector removes the light shielding shutter from the light path of the light from the light source and starts the analysis when receiving a signal for starting the analysis of the sample from the control unit. The liquid chromatograph according to claim 10, wherein an elapsed time from the start is measured, and the light-shielding shutter is arranged on the optical path when the time required for the analysis has elapsed since the start of the analysis. .
The mobile phase liquid feeding unit is configured to transmit a signal indicating that the mobile phase is being fed to the detector while the mobile phase is being fed,
While the light irradiation control means of the detector receives a signal indicating that the mobile phase is being fed from the mobile phase liquid feeding unit, the light shielding shutter is moved from the light path of the light from the light source. The shutter for light shielding is configured to be disposed on the optical path when the signal indicating that the mobile phase is being fed from the mobile phase feeding unit is not received. Liquid chromatograph.
An arithmetic processing unit for performing arithmetic processing on the sample based on the detection signal obtained by the detector;
A dark current data holding unit that holds a dark current value of an element of the photodetector measured in a state where the light blocking shutter of the detector is disposed on the optical path;
The arithmetic processing unit subtracts the dark current value held in the dark current data holding unit from the detection signal obtained by the detector during the measurement of the sample, and uses the sample for the arithmetic processing. The liquid chromatograph according to any one of claims 10 to 13, wherein
An analysis channel;
A sample introduction part for introducing a sample into the analysis flow path;
A mobile phase liquid feeding unit for feeding a mobile phase in the analysis flow path;
An analysis column provided on the downstream side of the sample introduction part on the analysis flow path, for separating the sample introduced by the sample introduction part for each component;
A liquid comprising: the detector according to any one of claims 6 to 9, which is provided on the downstream side of the analysis column on the analysis flow path and detects a sample component separated by the analysis column. Chromatograph.