JPS59107223A - Spectrochemical analyzer - Google Patents

Abstract

PURPOSE:To execute correct and precise absorbance measurement by continuously moving a reaction cell at a constant speed, exactly detecting the end face of this cell, and measuring light after a prescribed time. CONSTITUTION:Reaction cells 7 are fixed to a reaction table 6 at prescribed intervals and immersed in an annular thermostat water vessel 5. They are moved at a constant speed by rotation of the table 6. Light emitted from a light source 1 illuminates a sample in each cell through a light transmitting window 3, and the light transmitted through the sample is divided with a light dispersing element 10 into each monochromatic light of each wavelength, and converted into each electric signal with a detector 11. These signals are passed through amplifiers 15, 16, 17 and sample holding circuits 18, 19, 20, selected with a multiplexer 21, and converted into a digital quantity with an A/D converter 22. A CPU system 24 calculates a value of absorbance and stores it, and a series of processing is executed. The results of calculation are intermittently outputted with a timer 23.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an apparatus (1) for measuring the absorbance of a sample in a reaction cell (hereinafter referred to as a reaction cell).

[Technical background of the invention and its problems]

Conventionally, in the case of the so-called direct photometry method, in which the absorbance of the sample in the reaction cell is measured by irradiating light while moving the reaction cell containing the sample (the second method is to mechanically fix the reaction cell during photometry) A method has been considered in which the reaction cell is moved continuously and a sensor is used to detect when the reaction cell passes the photometric position.However, the method of mechanically fixing the reaction cell and measuring When a reaction cell with a large diameter C1 is used, ζ2 can be measured, but when a circular cell with a small diameter is used, there is a drawback that it cannot be fixed in a reproducible state. The method of detection with a sensor is to detect when the sensor reaches the center of the circular reaction cell, but the accuracy of the sensor is a problem, and its positioning is difficult, so it is difficult to always obtain accurate absorbance in a constant state. was difficult to measure.

Furthermore, a method was devised to capture and measure the peak of absorbance;
Since the cell is circular, the light is bent due to the difference in refractive index and the image moves on the entrance slit, so when observing a sample that absorbs light, the waveform changes as shown in 12, 13, and 14 shown in @2 Figure C2. It was found that it is difficult to accurately determine the peak from this waveform, and that the symmetry of the waveform changes depending on the concentration of the sample unless precise optical adjustment is performed. It was difficult to perform accurate and precise absorbance measurements from this peak.

[Purpose of the invention]

Therefore, the present invention has been made in view of the above circumstances, and
It is an object of the present invention to provide a spectroscopic analyzer that can perform accurate and precise absorbance measurements even when using a circular cell, especially a small diameter cell.

[Nakama of invention]

The basic principle of the present invention is to continuously move a reaction cell at a constant speed, accurately detect the end face of the reaction cell, and perform photometry after a certain period of time (usually when light passes through the center of the reaction cell). It is said that

[Embodiments of the invention]

Next, one embodiment of the present invention will be explained with reference to the drawings. Fig. 6 is a block diagram showing an embodiment of the present invention, and Fig. 4 is an explanatory diagram showing the waveform of a photometric signal. The absorbance measuring device of the present invention mainly includes a spectroscopic means for dispersing light transmitted through a sample into predetermined monochromatic light, a detecting means for photoelectrically converting the separated monochromatic light, and absorbance measurement based on the current output by the detecting means. Arithmetic processing means (hereinafter referred to as CP) that calculates
A CPU system (called U system), and a timer device which are connected to each other and emit a pulse signal at regular intervals.As shown in FIG. (The reaction cell is immersed in the ring-shaped thermostatic water tank 5, which has been added twice.) The reaction cell is transported at a constant speed by the rotation of the reaction table (2).

On the other hand, light from the light source 1 is applied to the sample in the reaction cell immersed in the constant temperature water bath 5 through the light transmission windows 6 and 4. The light transmitted through the reaction cell and the sample is separated into monochromatic lights of each wavelength by a dispersion element 10 and converted into an electrical signal by a detector 11 (2).The signal is sent to an amplifier 15. 19.20, it is discarded by the multiplexer 21, converted into a digital quantity by the AD converter 22, and stored (the absorbance value is calculated and stored in the two-CPU system 24, and a series of processing is performed. A system 24 (= is connected to a timer device @ 23 which inputs operation commands at intervals and outputs calculation results. Reference numerals 2 and 8 are lenses, and 9 is an entrance slit.

According to the present invention), two-sided light is always emitted at a certain position of the reaction cell where light is irradiated, and this will be specifically explained with reference to FIG. 4. That is, Figure 4 shows photometric signals of wavelengths of 25.27 and 25.27 that pass through the tube wall of the reaction cell measured with this device.
There are 26 sections in which light passes through the sample. The method of photometry is to set the time t from the end face to a certain position where light is passing through the sample, and then measure the time t.

When the light is applied to the sample (2)
If it is 6, the absorbance of the sample (- will change the waveform, so
Suite 25 with no sample applied (2) It is sufficient to set a threshold level consisting of 2 and judge this using a hardware or software comparator. Fluctuations in the light source (2 causes the size of the waveform to change, but the shape of the waveform itself changes. For example, if the threshold level is set to T of the level T when passing through the aquarium, it is possible to always detect the end face at the same position by following changes in the amount of light.

After a certain period of time from the passage of this end face, for example, find the time to until the center of the reaction cell passes, set this to in the timer device 26 (Ni), sample multiple wavelengths at that point (2), and measure the absorbance. To measure,
It is possible to measure the light of the sample in the reaction cell at a constant position at all times. For each reaction cell, it is necessary to memorize the exact time from the end face to the center (1), but the actual cell manufacturing accuracy depends on the diameter, eccentricity of the inner and outer walls of the reaction tube, etc. This is sufficient and can be treated as the same product.Also, when adding reaction cells, the optical path length error due to the inclination (-2) is not a problem (-), and the mounting position on the reaction table is such that the reaction cell itself is on the end face. Since it serves as a detection sensor, it also has the advantage that accuracy is not required.In the case of a circular cell, the photometry position can be arbitrary, but
The most advantageous position is through the center of the cell, where the absorption is maximum and the optical path length is easily controlled.

〔Effect of the invention〕

As described above, according to the present invention, passage of the end face of a reaction cell moving at a constant speed is accurately detected, and photometry at the same position (same optical path length) of the reaction cell is repeated after a certain period of time. This makes it possible to accurately and precisely measure the absorbance of circular cells, especially small-diameter circular cells.In particular, circular cells are easier to manufacture and have better cleaning efficiency than square cells. Due to its advantages, the device of the present invention can be of great use in automated biochemical analysis.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing the optical system, Fig. 2 is an explanatory diagram showing a photometric signal, Fig. 6 is a block diagram showing an embodiment of the device according to the present invention, and Fig. 4 is an explanatory diagram showing the waveform of the photometric signal. It is a diagram. 1...Light source, 2,8...Lens, 6,4...
・Light transmission window, 5... constant temperature bath, 6... reaction table, 7... reaction cell, 9... entrance slit,
10... Dispersion element, 11... Detector, 15,
16.17...Amplifier, 18.19.20...Sample and hold circuit, 21...Multiplexer, 2
2...AD converter, 26...timer, 24.
...CPU system, 25.27...Reaction tube wall,
26...Sample passage area. Agent Patent Attorney Kensuke Chika (and 1 other person) No.
1 Figure 2

Claims (1)

[Claims] A spectroscopic analyzer that spectrally spectra the light transmitted through a sample into monochromatic light and photoelectrically convert the light to measure the absorbance, which includes a transport means for transporting a reaction cell, a means for transporting a reaction cell, irradiating the reaction cell with light,
It has a spectroscopic means for dispersing the light transmitted through the sample, a detecting means for detecting the spectroscopic light and converting it into an electric signal (two electric signals), and an arithmetic processing means for inputting the photoelectrically converted signal and calculating the absorbance thereof. 1. A spectroscopic analysis device characterized by detecting and determining the passage of the front wall in the direction of movement of the reaction cell based on the output of the detection means, and measuring the light intensity after a predetermined period of time.