JP3755997B2 - Liquid chromatograph - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a liquid chromatograph, and more particularly to its spectrophotometer detector.
[0002]
[Prior art]
In various analyzers including liquid chromatographs, in order to increase the reliability of analysis, the accuracy of the analyzer is checked, so-called validation. In particular, in a liquid chromatograph using a spectrophotometer detector (UV detector) using UV-visible light, the accuracy of the wavelength of the UV detector, that is, UV detection, is one of the indexes indicating the accuracy of the UV detector. It is necessary to simply and accurately measure whether the instrument is detecting at the required precise wavelength.
[0003]
That is, the configuration of a conventional spectrophotometer detector of a liquid chromatograph is as shown in FIG. 2, but in the figure, 1 is a deuterium lamp as a light source of the detector, and this light is collected by the lens 2. The light enters the diffraction grating 4 through the slit 3. Then, the light that has been spectrally separated by the diffraction grating 4 and further condensed is made incident on the flow cell 6. The flow cell 6 has a cylindrical optical path, and a flow path 61 through which the effluent of the detection component separated by a liquid chromatograph column (not shown) flows is provided on the optical path. Therefore, the light irradiated to the flow cell 6 is transmitted through the liquid sample. The light passing through the flow cell 6 is detected by the photodiode 7.
[0004]
In the above configuration, when performing validation, the holmium filter 5 is inserted in the optical path, the wavelength at which the light absorption maximum is obtained is measured, and the accuracy of the wavelength is checked. That is, when the holmium filter 5 is inserted, the accuracy of the detector is checked based on whether or not the light absorption maximum is obtained in the same wavelength region of 360 nm as the holmium filter 5.
Also, without using the holmium filter 5, a method of checking the accuracy of the wavelength by sending an actual sample of known absorption maximum wavelength, such as caffeine, to the flow path 61 of the flow cell 6 and measuring the absorption maximum wavelength. It has been broken.
[0005]
[Problems to be solved by the invention]
However, although this method of inserting the holmium filter 5 is simple, its absorption maximum is in the vicinity of 360 nm, which is far from the wavelength range of 200 to 250 nm normally used for liquid chromatographic measurement. There was a disadvantage that the wavelength accuracy could not be checked in the wavelength range.
[0006]
In addition, the method of feeding an actual sample such as caffeine to the flow path 61 of the flow cell 6 can measure in a portion close to the practical wavelength range, but requires adjustment of the sample and feeding. Furthermore, since the absorption spectrum is generally not sharp but broad, there is a drawback that an error occurs in checking the wavelength accuracy.
[0007]
The present invention is intended to solve the above problems and provide a liquid chromatograph capable of easily checking the accuracy of the wavelength of the UV detector.
[0008]
[Means for Solving the Problems]
In order to solve the above problems, in the liquid chromatograph of the present invention, the deuterium lamp is constituted by a see-through deuterium lamp, and the light from the low-pressure mercury lamp and the low-pressure mercury lamp is placed in front of the see-through deuterium lamp. An optical system that leads to the see-through deuterium lamp is provided, and when performing validation to check the accuracy of the wavelength, the light from the low-pressure mercury lamp is transmitted through the deuterium lamp, and passes through the optical path of the see-through deuterium lamp. It is configured to be able to enter the photo detector. The light of this low-pressure mercury lamp has a strong emission line at a wavelength of 254 nm and is close to the wavelength range of the light used for the liquid chromatograph measurement, so that the wavelength accuracy can be easily checked.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the configuration of the high-performance liquid chromatograph according to the present invention, particularly its spectrophotometer detector, will be described with reference to one embodiment shown in FIG.
Reference numeral 11 denotes a deuterium lamp which is a light source of the detector, and reference numeral 2 denotes a lens. Light from the light source 11 is collected by the lens 2 and enters the diffraction grating 4 through the slit 3. Then, the light split and collected by the diffraction grating 4 is irradiated to the flow cell 6. The flow cell 6 has a cylindrical optical path, and a flow path 61 through which a liquid of a detection component separated by a liquid chromatograph column (not shown) flows. The light irradiated to the flow cell 6 passes through the liquid sample, and the light that has passed through the flow cell 6 is detected by the photodiode 7.
[0010]
Although the above configuration is the same as the conventional one, the present invention provides a hole 10 in the center of the inside of the deuterium lamp 11 of this light source, and constitutes a see-through deuterium lamp through which light can pass, An optical system including a low-pressure mercury lamp 8 and a lens 9 is provided in front of the optical system of the light source 11.
[0011]
In the above configuration, when performing validation for wavelength accuracy, the power of the see-through deuterium lamp 11 is turned off, and the light emitted from the low-pressure mercury lamp 8 is converged by the lens 9 and is reflected by the see-through deuterium lamp 11. A focus is formed at the center of the hole 10. The light that has passed through the hole 10 of the see-through deuterium lamp 11 is collected by the lens 2 and enters the diffraction grating 4 through the slit 3, and the light that is split and condensed by the diffraction grating 4 enters the flow cell 6. . The light that has passed through the flow cell 6 is detected by a photodiode 7. The low-pressure mercury lamp 8 has a strong emission line at a wavelength of 254 nm, and the actual wavelength used for the liquid chromatograph measurement is 200 to 250 nm. Both wavelengths are close to each other, so check the accuracy of the wavelength. It can be done more accurately. During normal measurement, the low-pressure mercury lamp 8 is turned off and the see-through deuterium lamp 11 is turned on, and analysis is performed by light emission from the see-through deuterium lamp 11.
[0012]
The characteristics of the present invention are as described above. However, the present invention is not limited to the above and illustrated examples. For example, the low-pressure mercury lamp 8 and the lens 9 may be detachable without being fixed. For example, a socket may be provided so that a lamp can be inserted during validation. The low-pressure mercury lamp 8 may be any light source that has a strong emission line in the wavelength region (200 to 250 nm) used for liquid chromatograph measurement. Including the light source. Furthermore, in the illustrated example, a high performance liquid chromatograph has been described as an example, but the present invention can be similarly applied to a normal liquid chromatograph.
[0013]
【The invention's effect】
As described above in detail, according to the present invention, the accuracy of the wavelength can be measured easily and accurately with the low-pressure mercury lamp 8 having high reliability. Further, since the emission line of the low-pressure mercury lamp 8 is 254 nm and the emission line of the deuterium lamp 11 is 486 nm and 656 nm, the combination of the low-pressure mercury lamp 8 and the deuterium lamp 11 allows the wavelength of the detector to be measured over the entire measurement wavelength range. Can be checked for accuracy.
[Brief description of the drawings]
FIG. 1 is a diagram schematically showing a configuration of an apparatus according to an embodiment of the present invention.
FIG. 2 is a diagram schematically showing a configuration of a conventional apparatus.
[Explanation of symbols]
1 …… Light source (deuterium lamp)
2 ... Lens 3 ... Slit 4 ... Diffraction grating 5 ... Holmium filter 6 ... Flow cell 7 ... Photo diode 8 ... Low pressure mercury lamp 9 ... Lens 10 ... Hole 11 ... Light source (see-through deuterium lamp)
61 …… Flow path

Claims (1)

The light from the deuterium lamp is dispersed by a diffraction grating, the light is irradiated to the flow cell through which the liquid sample separated by the column flows, and the light passing through this flow cell is detected by a photo detector to analyze the sample. In the liquid chromatograph to be performed, the deuterium lamp is composed of a see-through deuterium lamp, and an optical system for guiding light from the low-pressure mercury lamp and the low-pressure mercury lamp to the see-through deuterium lamp in front of the see-through deuterium lamp. The light from the low-pressure mercury lamp is transmitted through the see-through deuterium lamp when performing validation to check the accuracy of the wavelength, and can enter the photo detector via the optical path of the see-through deuterium lamp. A liquid chromatograph characterized by comprising.

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