JPS6385414A - Multibeam photometry instrument - Google Patents

Abstract

PURPOSE:To speedily measure plural samples by providing plural sample cells in the sample chamber of a spectrophotometer, irradiating those samples with measurement light in parallel or successively by switching, and detecting transmitted light in order. CONSTITUTION:Light from a light source 6 is dispersed by a spectroscope 8 to illuminate the six sample cells 4-1-4-6 in parallel through an optical fiber 12. Light beams passing through the cells are detected by detectors 10-1-10-6. The output signals of the detectors are amplified and integrated by amplifying and integration circuits 14-1-14-6 and applied to and converted by an A/D converter 18 in order through a multiplexer 16 into digital values, which are outputted to a data processing part. This multibeam constitution is employed to measure the plural samples at a high speed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a spectrophotometer, and particularly to a spectrophotometer capable of measuring a plurality of measurement samples.

(Prior Art) FIG. 7 shows an example of a spectrophotometer that can measure a plurality of samples.

In order to simultaneously measure, for example, six types of solutions in which chemical reactions are in progress using an ultraviolet absorption method, it is common to use a sample switching device commonly called a cell positioner.

In FIG. 7, reference numeral 2 indicates a six-row cell, and six sample cells 4-1 to 4-6 are provided. This cell 2 is reciprocated in the direction of the arrow by a cell positioner using a motor. 6 is a light source of measurement light, 8 is a spectrometer, and 10 is a detector.

The samples housed in the sample cells 4-1 to 4-6 are automatically switched by a motor, and the measurement light separated by the spectrometer 8 is passed through and detected by the detector 0. Sample cells 4-1 to 4-6
The switching is performed repeatedly at a cycle of, for example, once every 15 seconds, and the reaction progress of six solutions can be measured simultaneously.

(Problems to be Solved by the Invention) As shown in FIG. 7, in a spectrophotometer equipped with a cell positioner, the sample is mechanically moved and switched, so the measurement cycle cannot be made faster. One sample is measured for about 1 second, and the maximum cycle is 10 seconds round trip for six samples. Therefore, simultaneous measurements of fast reactions cannot be performed.

SUMMARY OF THE INVENTION An object of the present invention is to provide a spectrophotometer that can increase the measurement cycle of multiple samples and can quickly measure multiple samples even if the samples are not repeatedly measured.

(Means for Solving the Problems) In the spectrophotometer of the present invention, a plurality of sample cells for accommodating a measurement sample are provided in the sample chamber of the spectrophotometer, and measurement light is switched to these sample cells or connected in parallel. A light irradiation unit is provided to irradiate the sample cell, one detector is arranged in each sample cell, and a reading circuit is provided to sequentially read the signals of these detectors,
The output of this reading circuit is led to a data processing section via an A/D converter.

In this specification, such a spectrophotometer is referred to as a multibeam photometer.

(Embodiment) FIG. 1 shows a first embodiment of the present invention, in which the output of a spectrometer is divided by an optical fiber and each sample cell is irradiated with light in parallel.

The positions of sample cells 4-1 to 4-6 are fixed. 12
is an optical fiber as a light irradiation part, and optical fiber I2
has one entrance port and six exit ports, and the six exit ports are positioned so as to irradiate light onto the sample cells A-] to 4-6, respectively.

Detectors 10-1 to 10-6 are provided at positions for detecting the light transmitted through each sample cell 4-1 to /I-6, respectively. 14-1 to 14-6 are detectors 10-1 to 10-6
16 is a multiplexer that sequentially guides the outputs of the amplification/integration circuits 14-1 to 14-6 to the A/D converter 18. A
The output converted into a digital signal by the /D converter 18 is led to a data processing section.

The amplification/integration circuits 14-1 to 14-6 all have the same configuration, including a preamplifier 20 that amplifies the signals of the detectors 10-1 to 10-6, and a switch 22 that amplifies the signals of the preamplifier 20. The integrator 24 is provided with input via the integrator 24. In the integrator 24, a switch 26 is provided in parallel with the capacitor.

Switch 2 in amplification/integration circuits 14-1 to 14-6
2 is a controller that starts integration, and switch 2
6 is a switch for resetting the integrator 24. Integration is performed in the integrator 24 while the switch 22 is closed and the switch 26 is open. When the switch 26 is closed, the output of the integrator 24 is reset to prepare for the next integration.

=4- Amplification/integration circuits 14-1 to 14-6 and multiplexer 1
6 constitutes a reading circuit.

In this embodiment, the light from the light source 6 is separated by a spectroscope 8, and is irradiated in parallel to six sample cells 4-1 to 4-6 through an optical fiber 12. The light passing through the sample cells 4-1 to 4-6 is detected by detectors 10-1 to 10-6. In the amplification/integration circuits 14-1 to 14-6, after closing the switch 26 and resetting the integral output of the integrator 24, the switch 2 is closed again.
6, and all amplification/integration circuits 14-1 to 14-6
The switch 22 is closed for a certain period of time, for example, 20 milliseconds, and then the switch 22 is opened. This ends the integration, and since the integrator 24 is held at a constant value, the multiplexer 16 is switched over, for example, in 10 milliseconds, and the A/D converter 18 is sequentially connected to the amplification/integration circuit 14-1.
- Take in the output of 14-6. This means that 20 milliseconds out of 30 milliseconds are being measured in parallel.

Comparing this embodiment with the conventional spectrophotometer shown in FIG. 7, it is possible to follow extremely rapid changes in the six samples since this embodiment performs measurements almost all the time. On the other hand, the conventional spectrophotometer shown in FIG. 7 can only measure once every 10 seconds, so it is not possible to measure fast reactions.

On the other hand, since the light intensity is divided into six parts by the optical fiber 12 in this embodiment, only 1/6 of the light intensity can be obtained during the measurement period compared to the conventional one shown in FIG. However, since the measurement is carried out all the time, the irradiation time is six times longer, so there is no overall disadvantage in terms of light intensity.

FIG. 2 shows a second embodiment, in which semi-transparent mirrors 28-1 to 28-6 are used instead of optical fibers to split the luminous flux.

It is extremely difficult to obtain good transmittance in the ultraviolet region such as 200 nm with optical fibers, but beam splitting methods that do not use optical fibers, such as mirrors or semi-transparent mirrors, are not limited by such wavelength regions. .

Semi-transparent mirrors 28-1 to 28 which are light irradiation parts in this embodiment
The configuration other than -6 is completely the same as that of the embodiment shown in FIG.

FIG. 3 shows detectors 10-1 to 10- in the above embodiment.
6 shows a diode array 30 used in place of 6.

Since the readout circuit of the diode array 30 includes the same functions as the amplification/integration circuits 14-1 to 14-6 in the embodiment of FIG. 1, the detector 1 in the embodiment of FIG.
0-1 to 10-6 and amplification/integration circuits 14-1 to 14-6
In principle, it is equivalent to replace .

FIG. 4 shows yet another embodiment.

In this embodiment, the light irradiation unit temporally divides the irradiation light flux. The base end of the optical fiber 32 is connected to the outlet of the spectrometer 8, and the tip end of the optical fiber 32 is attached to a belt 35 that is reciprocated in the vertical direction by a motor 34.

The tip of the optical fiber 32 sequentially moves between the sample cells 4-1 to 4-6 by driving the motor 34, and sequentially irradiates the sample cells 4-1 to 4-6 with the output light of the spectroscope 8.

In this embodiment, in order to mechanically move the optical fiber 32,
Light switching is slower than in the embodiment of FIG.

In this embodiment, the reading circuit detects the detectors 10-1 to l0-.
The following two methods can be considered for extracting the signal from 6.

The first method is to use the amplifier/integrator circuit 1 as in the embodiment shown in FIG.
4-1 to 14-6 to respective detectors 10-1 to 10-
6, and the outputs of the amplification/integration circuits 14-1 to 14-6 are sequentially switched by the multiplexer 16 and guided to the A/D converter 18. In this case, the optical fiber 32
Accordingly, each of the sample cells 4-1 to 4-6 is irradiated only once in one cycle of irradiating the sample cells 4-1 to 4-6, and only this period of irradiation contributes to the integration.

Another example of the reading circuit is to receive light by switching the reading circuit side with a switch in synchronization with the irradiation of the sample cells 4-1 to 4-6 by the optical fiber 32, as shown in FIG. Switch 3 outputs of detectors 10-1 to 10-6
6, the signal is input to the amplifier 38, and the output signal of the amplifier 38 is guided to the data processing section via the A/D converter 18 (see FIG. 1). This eliminates the need for an integrating circuit,
The configuration of the reading circuit becomes simple.

FIG. 5 shows still another embodiment, in which a rotating mirror 42 is used as the light irradiation section.

The measurement light separated by the spectrometer 8 is reflected by a reflecting mirror 40 and enters a rotating mirror 42 that rotates in the direction of the arrow. Rotating mirror 42
The measurement light reflected by the sample cells 4-1 to 4-6 is sequentially irradiated with the sample cells 4-1 to 4-6. 44 is a mask provided in front of the sample cells 4-1 to 4-6.

The reading circuit in this embodiment has two
It can be achieved in the following way.

This embodiment can be said to be an example in which the light irradiation section has both mechanical and optical characteristics.

FIG. 6 shows still another embodiment of the present invention other than reaction tracking by simultaneous photometry as in the embodiment of FIG. 1.

44 is a microplate;
The electromechanical liquid 46 arranged in a rectangular shape in the vertical and horizontal directions can be measured in a short time.

On the upper part of the microplate 44, the irradiated light from the spectrometer is divided by the optical fiber 12, and eight measurement liquids 46 arranged in the vertical direction are simultaneously irradiated with the light.

The light transmitted through the measurement liquid 46 is transmitted to eight detectors 1°-1 to 10- arranged vertically below the microplate 44.
8 at the same time. That is, only the vertical direction is measured in parallel by eight detectors 1o-1 to 1°-6, and the horizontal direction is measured by moving the microplate 44.

In this embodiment, instead of measuring changes in a sample, samples in adjacent rows are measured one after another.

The same reading circuit as shown in FIG. 1 can be used as the reading circuit for reading the detection signals of the detectors 10-1 to 10-8.

Here, the multi-beam photometric device of the present invention will be compared with a conventionally used double-beam type photometric device.

The double beam method uses two beams on the sample side and the contrast side, and is used for the purpose of reducing drift by using the ratio of the transmitted light on the sample side and the transmitted light on the contrast side, that is, the difference in absorbance. On the other hand, the concept of the multi-beam method of the present invention is different from the conventional double-beam method in that "many samples are measured simultaneously or almost simultaneously." However, in the multi-beam method of the present invention, it is possible to have the effect of the double beam method as well by passing one of the irradiation lights through a sample cell that does not contain a sample, that is, contains an air section or a blank sample. can.

Variations between the individual beams of the light irradiation unit and each detector can be considered as follows.

For example, in the embodiment of FIG.
0 to 6 have different sensitivities. Also,
The light irradiation parts of the optical fiber 12 in the embodiment shown in FIG. 1 and the semitransparent mirrors 28-1 to 28-6 in the embodiment shown in FIG. 2 do not necessarily have to equalize the intensity of the light divided into each beam. That is, since each light beam and detector correspond to the same sample, when no sample is inserted, that is, the transmittance], O
0% or -11= is a state in which the absorbance is 0%, and the difference in transmittance ratio or absorbance from this state is due to variations in the light irradiated by the optical fiber 12 and the detectors 10-1 to 10-6. This is because it does not depend on variations in sensitivity.

Therefore, even if a large number of different detectors or light beam splitting elements such as optical fibers are used in the light irradiation section, there is no need to pay much attention to variations among them, and the system of the present invention can be easily adapted. can be assembled.

(Effects of the Invention) According to the present invention, a large number of samples can be measured simultaneously in parallel without switching between multiple samples, or the irradiation light can be switched to perform measurements, making it possible to follow fast reactions. can.

Even if the light is split, the loss in light amount is about the same as in the conventional case, so measurement accuracy does not decrease.

Furthermore, by setting one of the sample cells to be a blank sample or empty, it is possible to combine the advantages of the multi-beam method with the double-beam method.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing one embodiment of the present invention, Fig. 2 is a schematic diagram showing another embodiment, and Fig. 3 is a sectional view showing another example of the detector used in the present invention. 4 is a schematic diagram showing still another embodiment, FIG. 5 is a schematic diagram showing still another embodiment,
FIG. 6 is a schematic perspective view showing still another embodiment, and FIG. 7 is a schematic view showing a conventional spectrophotometer. 4-1 to 4-6... Sample cell, 10-1 to 10
-6...Detector, 16...Multiplexer, 18...A/D converter, 14-1 to 14-6...Amplification/integration circuit , 12
......Optical fiber, 28-1 to 28-6...Semi-transparent mirror, 30...
...Diode array, 32...Optical fiber, 36...Switch, 38...Amplifier, 42...Rotating mirror.

Claims (3)

[Claims] (1) A plurality of sample cells containing measurement samples are provided in the sample chamber of the spectrophotometer, and a light irradiation unit is provided for irradiating these sample cells with measurement light in a switched manner or in parallel, one for each of the sample cells. A multi-beam photometer is a multi-beam photometer in which two detectors are arranged, a reading circuit is provided to sequentially read the signals of these detectors, and the output of this reading circuit is guided to a data processing section via an A/D converter. (2) The light irradiation unit is of a type that selectively irradiates a plurality of sample cells with measurement light, and the reading circuit reads the signal by switching with a switch in synchronization with the switching of the measurement light irradiation. The multi-beam photometry device according to item 1. (3) The light irradiation section is of a type that irradiates measurement light to all sample cells in parallel, and the reading circuit always takes in the signals of the detector in parallel, integrates them, and outputs them sequentially. The multi-beam photometry device according to item 1.