JPS6128294B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention involves adding a reagent to a test sample to cause a reaction in which the absorbance gradually decreases, and optically measuring the temporal change in the reaction to analyze the test sample. Concerning methods for determining reaction rates for quantitative analysis of items.

In conventional reaction rate measurement devices, a reference cell and a sample cell with 100% light transmittance are used to determine the absorbance at the reaction rate measurement start point and measurement end point. The amount of transmitted light at that time and the amount of transmitted light when light transmitted through the sample cell were determined, respectively, and the absorbance at the reaction rate measurement start point and measurement end point was determined.

According to the conventional method, the transmittance was 100% as the standard, so in a reaction where the absorbance decreases over time, small changes in the absolute value of the absorbance are measured, so analysis using a digital microcomputer is necessary. Using an ordinary low-resolution analog-to-digital (AD) converter in the device had the drawback of increasing measurement errors.

An object of the present invention is to provide a reaction rate measurement method that allows highly accurate analysis even when the concentration of an analytical item is low.

A feature of the present invention is that in a method for quantifying an analysis item from the reaction rate of a reaction in which absorbance decreases, a transmitted light measurement value obtained when a reagent blank solution is introduced into a flow cell of a photometer is memorized as a reference value, The difference between the measured value based on the transmitted light obtained while the reaction solution of the test sample and the reagent is introduced into the flow cell and the memorized reference value is determined multiple times within a predetermined time, and the difference between this reference value and the measurement value is determined multiple times within a predetermined time. The reason is that the reaction rate is calculated based on the change in the difference between the two values.

In order to compare the conventional method and the method based on the present invention, a description will be made with reference to FIGS. 1 and 2.

First, conventionally, when measuring a test sample,
Water was introduced into the flow cell, and the measured value of transmitted light at this time was assumed to be 100% transmittance (T ₁₀₀ ) and used as a reference value. This value corresponds to zero absorbance in Figure 1.
X is ₀ . Then, at the measurement starting point, the difference X ₁ between X ₀ and the measured value A ₁ of the reaction solution is determined. That is, X ₁ = A ₁ − X ₀ Next, at the measurement end point, X ₀ and the measured value of the reaction solution A ₂
Find the difference X ₂ . That is, X ₂ =A ₂ -X _0The reaction rate of this sample is determined from the difference ΔX between X ₁ and X ₂ in the time interval (t ₂ -t ₁ ). However, in actual analysis operations, it is necessary to increase the processing efficiency of the analyzer, so the time interval (t ₂ - t ₁ ) cannot be made that large, so the difference ΔX between X ₁ and X ₂ is equal to X ₁ or
Very small compared to the value of X ₂ . In other words, conventional methods measure minute changes relative to large values.
The transmittance of 100% (T ₁₀₀ ) is several tens of times larger than the transmittance corresponding to the measured value A ₁ , so unless an AD converter with a very high resolution is used, Accuracy cannot be measured.

On the other hand, in the method based on the present invention, a reagent blank solution is introduced into a flow cell of a photometer when measuring a test sample. The transmitted light measurement value at this time is the reagent Planck measurement value X _B shown in FIG. This X _B becomes the reference when measuring the test sample. X at the measurement starting point
Find the difference X ₃ between _B and the measured value A ₃ of the reaction solution. That is, X ₃ = X _B − A ₃ At the subsequent measurement end point, X _B and the measured value of the reaction solution
Find the difference X ₄ from A ₄ . That is, X ₄ =X _B −A _4The reaction rate of this sample is determined from the difference ΔX between X ₄ and X ₃ in the time interval (t ₂ −t ₁ ). In this case, X ₄ and
The difference in size ΔX between X ₃ is smaller than the value of X ₄ or X ₃ . Therefore, the range of absorbance that can be handled by the AD converter is narrow, so high-precision measurements can be made even with an ordinary low-resolution AD converter.

Next, one embodiment of the present invention will be described with reference to FIGS. 3 to 5. Figure 3 is the overall configuration diagram, Figure 4
This figure is an explanatory diagram of the cell vicinity in FIG. 3, and FIG. 5 is an explanatory diagram of the signal processing system.

A test sample liquid, such as blood semen, contained in a sample cup 2 transferred by a sampler 1 is sucked and held in a suction/discharge tube 10 of a pipettor 3, and is discharged into an empty reaction cup 20 on a reaction line 18. The reaction cup 20 is then filled with a reagent solution 4. The reaction cup 20 is transferred through a constant temperature bath 21 by a reaction line feed mechanism 19. After a certain period of time, another reagent 7 is injected by the dispenser 5. At this point, the chemical reaction begins (1st to 2nd
(corresponds to t ₀ in the figure). Subsequently, the liquid to be measured in the cup 20 is guided into the cell 9 by the sipper 8. A chemical reaction is also progressing in the cell 9, and the amount of change in this reaction per unit time is determined. Next, the light from the lamp 11 passes through the cell 9 and enters the photometer 12, where it is separated by a diffraction grating 13 and reaches a detector 14. The output of the detector 14 is led to a digital processing section (microcomputer) 16 via a preamplifier 15. The change in absorbance of the sample per unit time determined by the digital processing section 16 is printed by the printer 17.
23 is a heat shield filter.

Cell block 2 equipped with constant temperature element 24 shown in Fig. 4
6 is equipped with a flow cell 9. On the reaction line 18, reagent blank solutions and sample solutions are arranged alternately.

Here, the signal processing system will be explained with reference to FIG. First, at the start of measurement, a reagent Planck's solution is introduced into the cell 9. As explained above, reagents are added to this reagent plank during the process of being sent through the reaction line. However, in a reagent blank solution, only the reagent is present and no chemical reaction occurs. Therefore, by measuring the reagent blank value in the cell 9, it is possible to measure the absorbance of only the reagent added midway. The amount of transmitted light based on the reagent blank liquid introduced into the cell 9 is measured by receiving the light emitted from the lamp 11 with the detector 14. That is, the measurement signal converted from an optical signal to an electrical signal by the detector 14 is amplified by the preamplifier 15 and sent to the AD converter 2.
5, converted into a digital signal, and then taken into the central processing unit 27 of the digital arithmetic processing section 16. The central processing unit 27 then stores the retrieved reagent blank value in the storage device 28.

Subsequently, a test sample is introduced into the cell 9, and the measured value is taken into the central processing unit 27 in the same manner as in the reagent plank described above. Here, if the amount of transmitted light of the reagent blank solution taken first is X _B and the amount of transmitted light of the test sample taken later is X ₃ , then the absorbance of the test sample with respect to the reagent blank solution is calculated from the above formula. can be found.

Also, the printing device 17 and printing control device 29 in FIG.
is for printing the absorbance of the standard sample determined by the central processing unit 27 and the concentration of the unknown sample determined from the calibration curve prepared using the standard sample. Furthermore, the mechanism control device 30 moves the cell block 26,
This is to prevent the light from the lamp 11 from entering the detector 14, and improves the accuracy of signal processing by measuring the eigenvalues (so-called getaways) of pure electrical systems such as the preamplifier 15 and AD converter 25. It is something. Although only one cell is shown in FIGS. 4 and 5, a plurality of cells may be used, and absorbance can be measured in the same manner as described above by moving these cells. In this case, it is possible to take a longer time after the test sample is injected into the cell, so it is possible to wait until the sample is stabilized, and more accurate measurements can be made.

As explained above, according to the present invention, the reverse state of the sample can be determined reliably and easily, so that a highly reliable reaction rate measuring method is provided.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of a conventional method, Fig. 2 is an explanatory diagram of a method based on the present invention, Fig. 3 is a diagram showing the overall configuration of an embodiment of the present invention, and Fig. 4 is an illustration of the embodiment shown in Fig. 3. FIG. 5 is an explanatory diagram of the signal processing system of the embodiment of FIG. 3. 9... Cell, 12... Photometer, 14... Detector, 16
...Digital arithmetic processing unit, 18...Reaction line, 2
0... Reaction cup, 26... Cell block, 27...
central processing unit, 28...storage device;

Claims (1)

[Claims] 1 Add reagents to the test sample to cause a reaction in which the absorbance of the reaction solution in which they are mixed decreases over time, determine the reaction rate from the change in the amount of absorbance of the reaction solution within a predetermined time, and calculate the reaction rate of the test sample. In a reaction rate measurement method for quantitatively analyzing analysis items for a test sample, the transmitted light measurement obtained when a reagent blank solution is introduced into the flow cell of a photometer is stored as a reference value in the memory of the reaction rate measurement device, and The difference between the measured value based on the transmitted light obtained while the reaction solution of and the reagent is introduced into the flow cell and the stored reference value is determined multiple times within a predetermined time, and the difference between the reference value and the measurement value is calculated multiple times within a predetermined time. A reaction rate measurement method characterized by determining the reaction rate based on a change in the difference between the value and the value.