JPH01277754A - Detecting apparatus for chromatograph - Google Patents

Abstract

PURPOSE:To execute precise discrimination as to whether a peak of a chromatogram is one of a single component or an incompletely separated one, by monitoring said peak for an actually continuous time and by comparing mutually the whole of an absorption spectrum of a prescribed wavelength band. CONSTITUTION:A liquid flowing out from a liquid chromatograph L is made to circulate through a flow cell F, while a light emitted from a light source P and transmitted through the flow cell F is made to enter a spectroscope M. This incident light is dispersed by a diffraction grating G and the spectral image thereof is formed on a photodiode array D. An output of the diode array D is converted into an absorbance signal through an absorbance conversion circuit Ad. CPW samples the signal obtained through the absorbance conversion, at a prescribed time interval. Then, as to one chromatogram peak, a correlation value of absorption spectrum data at a certain time point with absorption spectrum data of the same peak at another time point is calculated with the former absorption spectrum data used as a basis. This correlation value is displayed on a time base by an appropriate display means.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a chromatographic spectroscopic detection device.

(Prior art) When a spectroscopic method is used as a chromatographic detection method, 1
In addition to detecting the peak of 1 (in) 1 ram effluent acid content, it is also possible to determine whether the column effluent components have been completely isolated. Conventional methods for such spectroscopic detection include those that use three wavelengths and those that measure absorption spectra.

The three-wavelength method not only records the change in absorbance of the column effluent fluid to two wavelengths of light, but also records the ratio of the absorbances of the three wavelengths. If the chromatogram peak is of a single component, the absorbance ratio of the three wavelengths is constant throughout the peak period, so the absorbance ratio record becomes a square wave as shown in FIG. 2A. When a peak is the peak of incomplete separation of two components, there is a slight time lag between the peaks of the two components, so the absorbance ratio of the three wavelengths changes during the course of the peak, and the recording of the ratio is As shown in FIG. 2B, the upper side is a curved record, and depending on whether the ratio record is rectangular or non-rectangular, it can be determined whether the peak of the chromatogram is a single component peak or an incompletely separated peak. This method has several problems. One of them is that when the absorbance of the two wavelengths that becomes the denominator of the ratio is close to 0 for both components, the value of the ratio becomes large, the recording scales over, and the change in the ratio is recorded. It stops appearing. On the other hand, when the two components on the molecule side are small, the ratio value becomes small, and it becomes difficult to recognize the change in the ratio in the recording. Another problem is that if two components happen to have approximately the same absorbance ratio at three wavelengths, it will be difficult to recognize the change in the ratio on the record, and the peak will be mistaken for a single component peak.

The absorption spectrum is measured several times while the sample components are flowing out from the chromatograph, for example, once from the beginning of the flow (rise of the peak) to the top of the peak, once at the top of the peak, and once at the top of the peak. The absorption spectrum is measured by performing one wavelength scan three times between the peak and the end of the peak, and these absorption spectra are superimposed and Ml jl is performed. At this time, it is easier to understand if the maximum value of the absorption spectrum is recorded to be 1. If the chromatogram peak is a single component, the three absorption spectra records will match, but if it is an incomplete peak of two components, the three absorption spectra will not match each other, indicating that the peak is not a single component peak. Ru. This method involves looking at the ratio of absorbances at multiple wavelengths, which eliminates the problem that existed in the case of three wavelengths, but data is collected at several points on the time axis for one peak. Because of this, small peaks such as those located between two data collection points may be overlooked, and in this respect, the method is inferior to the three-wavelength method, which observes chromatogram peaks continuously over time.

(Problem to be solved by the invention) It is possible to improve the imperfection of each fq, whether it is a single component peak or an incompletely separated peak, which is a drawback of the method using light of three wavelengths, and to solve the problem of the absorption spectrum inter-chamber method. The aim is to improve the roughness of measurement points on the time axis, which is a drawback, and to obtain the same results as actually measuring absorption spectra continuously.

(Means for solving the problem) The absorption spectrum data of the fluid flowing out of the column is sampled at appropriate time intervals using a one-dimensional imaging device, and the absorption spectrum data at a certain point in time is used as a reference for one chromatogram peak. Then, the correlation value between the absorption spectrum data and the absorption spectrum data at other times of the same peak was calculated, and the correlation value was displayed on the time axis using an appropriate display means.

(Operation) Let AI(λ) be the data of the absorption spectrum at the time of the rise of the peak of the chromatogram, and let A2(λ) be the sampling data of the absorption spectrum at an arbitrary sampling time of the same peak. Since these are absorption spectrum data, they are functions of wavelength. If the peak is a single component peak, then if the constant K is determined appropriately, A1 (λ) = K
A2(λ). For example, the correlation R between AI(λ) and A2(λ) is calculated. If the peak is a single component, Δ1(λ)=K
Since A2(λ), the correlation value R is 1, and when the peak is an incompletely separated peak, A2(λ) varies depending on the sampling time, and in this case AI(λ) −KA2 (
λ), and in this case R is O≦R
<1, and the larger the difference between the two absorption spectra, the more R
is a small value. Therefore, if the correlation R is recorded over time for one peak, if it is a single component peak, R
shows 1 throughout the entire period of the peak, and if it is a peak due to incomplete component separation, R is smaller than 1 and changes over time, so it can be directly identified.

(Example) FIG. 1 shows an example of the present invention. ■, is a liquid chromatograph, F is a flow cell, and liquid chromatograph■
, the effluent from is distributed. P is a light source, and the light from the light source P that has passed through the flow cell F is made to enter the spectroscope M. This light is dispersed by the diffraction grating G and forms a spectral image of the flow cell transmitted light on the photodiode array D.

The CPU is a central processing unit that performs various m1r controls and calculations. The ROM is a ROM that stores various control and calculation programs performed by the central processing unit. The output of the photodiode array D is converted into an absorbance signal through an absorbance conversion circuit Δb. The CPU zumbling the output signal of the photodiode array D whose absorbance has been converted at regular time intervals, A/D converting it using an A/D converter (AI), and importing the absorbed absorption spectrum in the wavelength axis direction. When this integral value becomes constant and exceeds Bell ΔA, the sample components begin to flow out from the chromatograph (it is judged as the rise of the chromatograph peak), and at that point '1゛0. Absorption spectrum data Δ0(λ
) is stored in memory In. Absorption Spec I will continue from now on.
- Performs embedding of all data, integrates the absorption spectrum, and stores the embedded absorption spectral data A1(λ), 82(λ), etc. in memory m. On the other hand, the absorption spectrum Ao(λ) of the TO feature point and the absorption spectrum Ai(λ) at each subsequent sampling point
) is calculated in real time and output to the recorder () to record the correlation value R on the recording paper.The calculation of the correlation value R is written in integral form in equation (1), but CI When using 'U', specifically, when the wavelength measurement range is divided by Δλ and the wavelength of the dividing point is λ0 (n"0.1+2・
...p) to find R. The above-described operation is continued until the integration of the absorption spectrum becomes equal to or less than a predetermined level ΔΔ. This operation is also performed on other chromatogram peaks.

When the correlation value R is calculated and displayed in real time, the absorption spectrum at the top of the chromatogram peak is used as a reference to calculate the correlation with the absorption spectrum at other sampling times.
When calculating and displaying R over time using the data within, for example, it is possible to calculate and display the correlation between the absorption spectrum at other sampling points based on the absorption spectrum at the top of the peak. good.

(Effects of the Invention) According to the present invention, the peaks of the chromatogram are monitored virtually continuously in time, and the entire absorption spectra in a certain wavelength range are mutually compared. Compared to monitoring or comparing absorption spectra at several points within a chromatogram peak, monitoring is performed at a much higher density on the wavelength axis and on the time axis -L compared to conventional methods, and the chromatogram It is much easier and more reliable to determine whether a peak is a single component or an incompletely separated peak of multiple components than with conventional methods.Furthermore, with the method of recording the absorbance ratio across three wavelengths, as mentioned above, Depending on the method of selection, the ratio value may scale over the recording device or be too small, making it difficult to judge, so wavelength selection has been difficult, but the present invention eliminates such troublesome wavelength selection. (,
Since the maximum value of the correlation value R is 1, it is easy to set the range of the recorder, and the magnitude of the correlation value R indicates a value related to the purity of the chromatodarum peak, so that value can be used for various automations. In addition, it becomes easy to intuitively understand how the purity of the chromatogram peak changes over time.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an apparatus according to an embodiment of the present invention, and FIG. 2 is a diagram illustrating the problems of the three-wavelength method. L...Liquid chromatograph, M...Spectrometer, F...
・Flow cell, P... light source, G... diffraction grating, D...
...Photodiode array, Δd...Absorbance conversion circuit, CI)U...Central processing unit, m...Memory, ■
ri...Recorder. Agent Patent Attorney Kosuke Agata

Claims (1)

[Claims] The absorption spectrum data of the fluid flowing out of the column is sampled at appropriately short time intervals using a one-dimensional imaging device, and for one chromatogram peak, the absorption spectrum data at a certain point in time is used as a reference, and the same absorption spectrum data is obtained. A chromatographic detection device characterized in that a correlation value between a peak and absorption spectrum data at other points in time is calculated, and the correlation value is appropriately displayed on a time axis by a display means.