JPH0692933B2 - Thin layer chromatographic scanner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to thin-layer chromatography to scan the spots in a zigzag pattern with a light beam and measure the reflected light or transmitted light to determine the shape and concentration of the spots. The present invention relates to so-called thin layer chromatography that is used for detection.

B. Conventional technology Generally, in thin-layer chromatography, there is a problem that the reference level of the measurement signal fluctuates due to variations in the distribution of substances contained in the thin-layer plate itself.To minimize this error, zigzag A method of resetting the reference level for each swing of the skiyan is adopted. FIG. 1 (a) shows the trajectory of the measured light beam at the time of zigzag scanning, in which the light beam is swung left and right with a sufficiently large width including the sample spot P, and the starting point of each swing, that is, the left and right ends of the light beam trajectory. The measurement output at is defined as the reference level. FIG. 1 (b) shows a photometric output curve for one swing, which has a shape in which the spot waveform is superimposed on the back ground level of the thin layer plate. In the figure, the background level L ₁
The area S of the shaded area above is obtained by the integrating circuit and becomes a chromatographic signal.

The conventional method as described above is not problematic when the back ground level is flat and the reference levels L ₁ and L ₂ set at the left and right ends are equal to each other as shown in FIG. If the concentration of the contained substance is uneven, and there is a gradient in the background level just at the spot, the following problems occur. That is, FIG. 2 shows a measured output curve in one reciprocating scan, FIG. 2 (a) shows a rightward swing, and FIG. 2 (b) shows a leftward swing. In the case of the figure (a), the reference level is set to L _1, and since it is an upward slope, the triangular area below the reference level is additionally added to the true area. In the case of the figure (b), the reference level is The output of the integrator circuit, i.e. the chromatographic signal, is smaller than the true area, because it is set to L ₂ and the slope is down and the part where the measured output is below the reference level L ₂ is integrated as a negative area. Will indicate the value. As a result, the chromatographic signal curve obtained by plotting each chromatographic signal in the Y direction of scanning has many irregularities as shown by the solid line in FIG. 3, and when the peak is detected in the signal processing circuit, the peak start position and peak are detected. There is a drawback that an error is likely to occur in detection of the end position, peak maximum value and the like. In the figure, the broken line is the chromatographic output waveform when the back ground level has no gradient.

(C) Purpose The present invention aims to solve the above problems and improve the accuracy of peak position detection and the like by reducing the unevenness of the chromatographic signal curve.

D) Configuration To achieve the above object, the present invention is configured such that the average value of the integrated value at the time of the rightward swing and the integrated value at the next leftward swing is used as a chromatographic signal in skining, and therefore the light reception is performed for that purpose. 2 adjacent to each other between the integration circuit that integrates the measurement output from each unit for each swing and outputs the integrated value as a chromatographic signal and the signal processing circuit that processes the chromatographic signal and performs peak detection, etc. The averaging circuit for averaging the chromatographic signals of No. 1 into one chromatographic signal is provided.

E, Embodiment FIG. 4 is a block diagram showing an embodiment of the present invention. The measurement circuit (1) receives the output of the light receiving element (2) and outputs a measurement signal proportional to the amount of light absorption. The integrating circuit (3) integrates the measured output for one swing of the light beam with the photometric output at the swing start point as a zero level and outputs the integrated value as a chromatographic signal. At the output of the integrating circuit (3), a chromatographic signal by a leftward swing as shown in FIG. 2 (a) and FIG. 2 (b).
The chromatographic signal due to the rightward swing such as is alternately included. Therefore, if two consecutive chromatographic signals are averaged in sequence, the effect of the background level gradient is canceled by the reciprocating swing and the true integration is performed. A chromatographic signal close to the value can be obtained. The averaging circuit (4) in FIG. 4 is for that purpose. The new chromatographic signal thus obtained is input to the signal processing circuit (5), where the result is obtained after signal processing such as peak detection is performed. Display device (6)
Is displayed in.

FIG. 5 is for explaining the operation of the averaging circuit (4). Now, the reference level at the left end is L ₁ , and the reference level at the right end is L _2.
Assuming that the measured output waveform during the reciprocating swing hardly changes, the true area is A + B, the area value during the rightward swing is A + B + D, and the area value during the leftward swing is AC. On the other hand, from the symmetry of the figure, D =
Since it is B + C, the sum of the area values at the time of the left and right swing is (A + B + D) + (A−C) = 2A + B + B + C−C = 2
(A + B), and the average value can be regarded as the true area A + B.

E. Effect As described above, the present invention averages two continuous chromatographic signals and converts them into one new chromatographic signal between the integrating circuit and the signal processing circuit of the conventional thin layer chromatographer. Due to the extremely simple configuration of providing a conversion circuit,
Advantages of eliminating unevenness in the chromatographic output waveform caused by the background level gradient and reducing signal processing errors such as peak detection by making it closer to a smooth true chromatogram and improving analysis accuracy There is.

[Brief description of drawings]

1 to 3 are for explaining a conventional example.
Figure (a) is an explanatory diagram showing the locus of the measurement light beam, (b) is a measurement output waveform diagram, and (a) and (b) are rightward swing and leftward when the back ground level has a gradient. FIG. 3 is a chromatographic output waveform diagram of the measurement output waveform during a swing. FIG. 4 is a block diagram of an apparatus showing one embodiment of the present invention, and FIG. 5 is an operation explanatory diagram of the same. (1) ... light receiving part, (2) ... light receiving element, (3) ... integrating circuit, (4) ... averaging circuit, (5) ... signal processing circuit, (6) ... display device, P …… Sample spot, L ₁ L ₂ …
... reference level, S ... area value.

Claims (1)

[Claims] 1. A measurement light beam is swung left and right to scan a sample spot in a zigzag manner, and the light receiving unit output is integrated by setting the light receiving unit output at an integration start point to a reference level for each swing by an integrating circuit, A thin layer chromatograph, characterized in that an integrated value output is inputted as a chromatographic signal to a signal processing circuit, and an averaging circuit for averaging two adjacent chromatographic signals into one chromatographic signal is provided. Scanner.