JPS5930027A - Spectrophotometer - Google Patents

Abstract

PURPOSE:To improve the efficiency of the measurement of absorbance, by providing a proportional logarithm amplifier and a constant polarity output means, which is characterized by the constant polarity output regardless of the output polarity, in a light measuring circuit. CONSTITUTION:Luminous flux from a monochrometer 12 is divided into two parts by a semitransparent mirror 13. One part of the flux is inputted to a flow cell 14 and a current signal IS is outputted from a light detector 16. The other part is inputted to a square cell 15 and a current signal IR is outputted from a light detector 17. The signals IS and IR are inputted to a proportional logarithm amplifier 18. Its output is displayed on a display device 23 through a constant polarity output means 19, an A/D converter 20, and the like. At this time, the output voltage from the amplifier 18 is switched by a switch SW in response to the output from an operation processing device 21 based on a mode from an input device 22, in the means 19. Thus, any luminous flux of a plurality of luminous fluxes can be measured.

Description

[Detailed description of the invention] [Technical field of invention] This invention belongs to the technical field of spectrophotometers.

[Technical background of the invention and its problems]

Conventional spectrophotometers, especially automated chemical analyzers for clinical testing (
The spectrophotometer installed at the station is constructed as shown in FIG.

As shown in FIG. 1, the source emitted from the light source 1 is converted into a monochromatic light by a monochromator 2TL, and the monochromatic light emitted from the monochromator 2 is divided into two beams by an optical system 3. On the optical path of each divided beam, a fixed cell such as a flow cell 4 and a removable cell such as a corner cell 5 are arranged for measuring the absorbance of a test sample. A chopper 6 is disposed at the rear of the flow cell 4 and the corner cell 5, and a photodetector, for example, a photomultiplier 7, is disposed behind the flow cell 4 and the corner cell 5. The chopper 6VC continuously cuts one of the double beams, and the other is connected to the flow cell. The transmitted light transmitted through the flow cell 4 or the corner cell 5 is incident on the photomultiplex 7, and the photomultiplex 7 outputs a current signal according to CM. The current signal output from Photomaru 7 is I/V
After being converted into a voltage signal by the converter 8, it is outputted to either the absorbance measurement circuit or the photomultiply stabilization circuit by the switch SIV linked to the chopper B.

The circuit for absorbance measurement includes a logarithmic amplifier AAIp and a D converter ADC, and the absorbance of the test sample in the flow cell 4 is calculated based on the input voltage signal.

On the other hand, the photomultiply stabilizing circuit has a comparator C0AIry which compares the input voltage signal with the reference voltage.
C-1) C:1
The output of the converter 9 is fed back to the photomultiplex 7Vc to maintain the stability of the output current of the photomultiplex 7.

However, in the 41111-component spectrophotometer, only the one-element bundle out of the two-element bundles split by the optical system 3 is used for measuring the absorbance of the test sample. Therefore, the efficiency of absorbance measurement is poor, and in particular, in order to remove the absorbance AblK for pure water caused by a specific component from the absorbance AblK for pure water of the test sample, it is necessary to
A sample containing a specific component must be placed in the flow cell 4 to measure its absorbance AhlK, then a test sample must be placed in the flow cell 4 to measure its absorbance A, and its edge s''J AbsK must be calculated. It's complicated.

[Purpose of the invention]

This invention was made in view of the above-mentioned circumstances, and is a spectrophotometer that improves the efficiency of absorbance measurement by using both of the restored bundles divided by the optical system to determine the absorbance i1+11 of the sample $-1. The purpose is to provide the following.

[Summary of the invention]

The outline of the present invention for achieving the above object is to provide a fixed cell in one of the double beams and a fixed cell in the other beam.
In a double-beam photometry spectrophotometer equipped with a cell that can be removed from the This device is characterized in that photometry can be performed using any of the light beams.

[Embodiments of the invention]

FIG. 2 is a schematic block diagram showing one embodiment of the present invention.

A spectrophotometer which is an embodiment of the present invention is constructed as follows. Specifically, in FIG. 2, reference numeral 11 indicates a light source that emits white light, and reference numeral 12 indicates a device for extracting monochromatic light from the white light from the light source 11, such as a monochromator. Reference numeral 16 indicates a semi-transparent mirror, which divides the light flux emitted from the monochromator 12 into two.

Reference numeral 14 indicates a flow cell, which is placed on the optical path of the light beam transmitted through the semi-transparent mirror 16. Reference numeral 15 denotes a cell holder, which is disposed on the optical path of the light beam reflected by the semi-transparent mirror 13 and can detachably hold the square cell without blocking the light beam. Reference numeral 16 denotes a photodetector, which is disposed on the optical path of the light beam that has passed through the flow cell 14, and generates a current signal Is according to the amount of light in the light beam (which has passed through the flow cell 14 containing the test sample). Output.

A photodetector 17 is disposed on the optical path of the light beam that has passed through the corner cell 15, and outputs a current signal IR in accordance with the amount of light that has passed through the corner cell 15. 18 is a proportional logarithmic amplifier, and the current signal IB of the photodetector 16 on the flow cell 14 side and the current signal JR of the photodetector 17 on the corner cell 15 side are calculated by the following equation 1. The voltage E is obtained by performing the calculation according to the following. Output ut.

Eo, Lt = Kloy (Is/IR) ・-・
-.-(1) (K is a proportional coefficient) 19 indicates a constant polarity output means, such as a switching circuit, and a polarity inverter 19. f and a changeover switch J, and outputs an output command output voltage E from the arithmetic processing unit 21 according to a mode inputted from an input device 22, which will be described later. 1t is output as is, and a voltage Eout obtained by positively inverting the proportional logarithmically amplified output voltage Eou, t by polarity inverters 19 and 4 is configured. Reference numeral 20 indicates a converter 1, and the voltage I Eou output from the switching circuit 19 is
tI is subjected to 4ω conversion, and the obtained digital signal is outputted to the arithmetic processing unit 21VC.

The arithmetic processing device performs arithmetic processing such as correction processing or density conversion based on the input digital signal, and displays the results on the display device 23. Incidentally, numeral 22 indicates an input device for inputting data regarding the analysis mode isobaric.

Since the spectrophotometer is configured as described above, for example, from the absorbance A to pure water due to a specific component in the test sample, to the absorbance Ah to pure water due to other components in the test sample.
When trying to determine the absorbance A of a specific component after +K has been removed, the specimen sample is poured into the flow cell 14,
Further, the square cells 15 are filled with reagents containing the same components as the other components in the 11 specimen samples, and the absorbance of each is measured. Then, the one-element detector 16 outputs a current signal 1 (3) and the photodetector 17 outputs a current signal JR.
The proportional logarithm amplifier 18 calculates the absorbance according to the above-mentioned equation (1) using the input value as input. In equation (1), 1o
, qcIEv/JR) = 1oy18-1oy1R, the voltage Eo output from the proportional logarithmic amplifier 18
It can be said that tLt represents only the absorbance due to a specific component in the test sample after removing the absorbance due to other components in the test sample. Output voltage E of the proportional logarithmic amplifier 18. Switching circuit 1 regardless of whether ut is positive or negative
9 inputs the positive output voltage Eout to the ω converter 20. Various arithmetic operations can be performed on the digital signal output from the A/D converter 20, and the results can be displayed on the display device 23. In this way, since both of the multiple beams are used for absorbance measurement, the efficiency of absorbance measurement is high, and it is possible to measure the absorbance of a specific component in a test sample in a single measurement. can.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above-mentioned embodiment, and it is to be understood that the present invention can be modified and implemented as appropriate without changing the gist of the invention. It's not even a cough.

As another embodiment, as shown in FIG.
A spectrophotometer using a DK converter 24 can be mentioned. Since the bipolar input type A/D converter 24 has a positive output polarity regardless of the polarity of the input, if the bipolar input type A/D converter 24 is used, the above-mentioned embodiment The configuration can be simplified by omitting the switching circuit.

〔Effect of the invention〕

According to this invention, any of the divided multiple beams can be used for the absorbance measurement pressure of each sample to be tested, and the efficiency of measurement can be improved. When a reagent containing a component to be neglected in a test sample is stored in a removable cell, and a test sample is stored in a fixed cell and the absorbance is measured, ○ components to be neglected in the test sample are stored. Absorbance for other specific component pressures can be obtained in one measurement.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a conventional spectrophotometer, FIG. 2 is a block diagram showing one embodiment of the present invention, and FIG. 6 is a block diagram showing another embodiment of the present invention. 14...Flow cell (fixed cell), 15...
Cell holder, 18... Proportional logarithmic amplifier, 19...
・Switching circuit, 24...Polarity reversal ω converter.

Claims (1)

[Claims] In the spectrophotometer of the double-beam photometry method, in which a fixed cell is placed in one of the light beams and a removable cell is placed in the other beam, the photometry circuit has a proportional logarithmic amplifier and a proportional logarithm amplifier output polarity. and a constant polarity output means which outputs the output with a constant polarity regardless of the polarity.
(Stayed once.