JPH01321324A - Spectrophotometer capable of measuring two or more samples - Google Patents

Abstract

PURPOSE:To simultaneously measure a plurality of samples by rotating the reflecting mirror mounted on a rotary shaft by a measuring light change-over mechanism to change over measuring light. CONSTITUTION:When a rotary shaft 4 is rotated by a motor 8 and measuring light 12 is allowed to be incident, the measuring light 12 is successively changed over by the reflecting mirrors 6 (6-1 - 6-4) of a measuring light change-over mechanism to successively pass through samples 2 (2-1 - 2-4) and detected by a photodetector 18 through optical fibers 16-1 - 16-4. The rotation of the rotary shaft 4 is detected by a rotation detector 14 and a rotation detection signal is outputted. When the wavelength of the measuring light 12 is fixed and measurement is performed while the measuring light is allowed to be successively incident to the samples 2 by the measuring light change-over mechanism, the timewise changes of the absorbancies of four samples can be simultaneously measured. By scanning the wavelength of the measuring light 12, the spectra of four samples 2 can be simultaneously measured.

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 samples.

Spectrophotometers that measure multiple samples include, for example, ultraviolet and visible spectrophotometers, as well as automatic biochemical analysis devices such as blood test devices that distribute blood into multiple cells and perform simultaneous measurements by placing different enzymes in each cell. It is used in devices that flow chemicals through flow cells, measure them, and perform process control.

(Prior art) In order to measure multiple samples at the same time, there is a method in which the measurement light is distributed into multiple beams using an optical fiber and each beam is incident on the corresponding sample. There is a method in which samples are sequentially placed on one optical path.

Note that the word "simultaneously" in simultaneous measurement does not only mean simultaneous in the strict sense of the word, but also includes, for example, measuring multiple samples in a short period of time even if they are different in time. Use as.

(Problems to be Solved by the Invention) In the method of distributing the measurement light into a plurality of parts using an optical fiber, the energy of the measurement light per sample is dispersed, resulting in a poor S/N ratio.

Further, since the intensity of each measurement light distributed by the optical fiber varies, the linearity of absorbance deteriorates.

In the method of moving the sample using a cell positioner, since the sample is mechanically moved and switched, the period during which measurements are not possible when switching samples becomes long, and the measurement cycle cannot be shortened. For example, when measuring 6 samples, 10
It is only possible to measure one period in seconds, and simultaneous measurement of fast reactions is not possible.

The present invention efficiently utilizes the energy of measurement light to achieve S/N
A spectrophotometer that can increase the ratio and perform measurements at short intervals, acquiring measurement data almost continuously, measuring time changes of multiple samples at the same time, and measuring spectra at the same time. The purpose is to provide the following.

(Means for Solving the Problems) The present invention includes a measurement light switching mechanism that sequentially switches measurement light to enter a plurality of fixedly arranged samples, and a single light detection system that detects the measurement light that has passed through the sample. A light receiving part that receives light on the device,
It includes a rotation detection section that detects the switching position of the measurement light switching mechanism, and a data processing section that processes the measurement signal of the light receiving section based on the detection signal of the rotation detection section. In the measurement light switching mechanism, a plurality of reflecting mirrors corresponding to each sample are attached to a rotating shaft, and each reflecting mirror has a different position in the rotational axis direction and is tilted with respect to the rotational axis direction. It occupies an equal angle of rotation with respect to the direction of incidence.

(Function) When the rotating shaft to which the reflecting mirrors are attached by the measuring light switching mechanism rotates, the reflecting mirrors that reflect the measuring light are sequentially switched. Measurement light enters the corresponding sample from each reflecting mirror for a certain period of time corresponding to the rotation angle occupied by each reflecting mirror. The measurement light is not distributed to each sample, but is entirely reflected and incident on the sample.

The measurement light that has passed through the sample is guided to a single photodetector at the light receiving section and detected. The data processing section discriminates the measurement signal of the light receiving section based on the detection signal of the rotation detection section and performs data processing for each sample.

(Example) Figure 1 shows a plan view of the part excluding the data processing unit in an example. Figure 0 shows an example in which four samples are arranged, but the number of samples is three. The number may be less than or equal to 1, or may be even larger.

Samples 2-1 to 2-4 are placed in sample cells. The positions of samples 2-1 to 2-4 are fixed.

In order to make the separated measurement light 12 incident on the samples 2-1 to 2-4, a rotating shaft 4 is attached parallel to the arrangement direction of the samples 2-1 to 2-4. Four plane reflecting mirrors 6-1 to 6-4 are attached to the rotating shaft 4 in order to reflect the measurement light 12 and make it incident on the corresponding samples 2-1 to 2-4, respectively. The rotating shaft 4 is rotated by a motor 8 via a belt 10. A rotation detector 14 such as a rotary encoder is attached to the rotating shaft 4, and the rotation angle of the rotating shaft 4 is detected.

Optical fibers 16-1 to 16-4 are arranged on the opposite side of the reflectors 6-1 to 6-4 with respect to the samples 2-1 to 2-4, and the optical fibers 16-1 to 16-4 are bundled. and is guided to a single photodetector 18. Measurement light 1 that has been sequentially reflected by reflecting mirrors 6-1 to 6-4 and passed through samples 2-1 to 2-4
2 is connected to the photodetector 1 via optical fibers 16-1 to 16-4.
Detected at 8. As the photodetector 18, for example, a photomultiplier tube or the like can be used.

The reflecting mirrors 6-1 to 6-4 are attached to the rotating shaft 4 so as to sequentially switch the measurement light 12 and make it incident on the samples 2-1 to 2-4. The rotating shaft 4 and the reflecting mirrors 6-1 to 6-4 are shown in FIGS. 2, 3, and 4. Reflection 1'16-1~6-
4 are arranged on the rotating shaft 4 at different positions in the axial direction of the rotating shaft 4, and are mounted at an angle with respect to the axial direction of the rotating shaft 4 so as to reflect the measurement light 12 and make it incident on the corresponding sample. It is being In this embodiment, the measurement light 12 is incident parallel to the rotation axis 4, and each of the reflecting mirrors 6-1 to 6-4 is inclined at 45 degrees with respect to the rotation axis direction. Further, as shown in FIG. 3, the center positions of the respective reflecting mirrors 6-1 to 6-4 are arranged to be shifted from each other by 90 degrees with respect to the rotational direction of the rotating shaft 4.

As shown in FIG. 2(A), from the position where the measurement light 12 is now reflected by the reflecting mirror 6-1 and enters the sample 2-1,
When the rotating shaft 4 rotates 90 degrees counterclockwise when viewed from the measurement light incident direction, the measurement light 12 is reflected by the reflecting mirror 6-2 and enters the sample 2-2, as shown in FIG. . In this way, as the rotation shaft 4 rotates, the measurement light 12 is sequentially switched and incident on the samples 2-1 to 2-4.

FIG. 5 shows an example of the data processing section.

The output line of the photodetector 18 is connected to sample hold circuits 22-1 to 22-4 corresponding to each sample 2-1 to 2-4 via a demultiplexer 2o. The operation of the demultiplexer 20 is controlled by a rotation detection signal from the rotation detector 14, and each sample and hold circuit 22-1 to 22-4
is the measurement light 1 that has passed through each sample 2-1 to 2-4.
The detection signal of the photodetector 18 by 2 is held and output.

Next, the operation of this embodiment will be explained.

When the rotary shaft 4 is rotated by the motor 8 and the measuring light 12 is incident, the measuring light 12 is reflected by the reflecting mirror 6- of the measuring light switching mechanism.
Samples 2-1 to 2 are sequentially switched by 1 to 6-4.
-4, and is detected by the photodetector 18 via optical fibers 16-1 to 16-4.

The detection signal of the photodetector 18 is repeatedly obtained from samples 2-1 to 2-4 in the order shown in FIG. On the other hand, the rotation detector 14 detects the rotation of the rotating shaft 4 and outputs a rotation detection signal shown in FIG. While the rotation detection signal is on, the corresponding gate of the demultiplexer 20 is turned on, and the photodetector signals are sampled and held in the respective sample and hold circuits 22-1 to 22-4. The signals held in the sample and hold circuits 22-1 to 22-4 are held until the photodetector signal of the corresponding sample is sampled in the next cycle.

By fixing the wavelength of the measurement light 12 and making measurements while sequentially making the measurement light 12 incident on the samples 2-1 to 2-4 using the measurement light switching mechanism, it is possible to simultaneously measure changes in absorbance over time for the four samples. can be measured. FIG. 7 shows an example of the change in absorbance measured in this way over time.

By scanning the wavelength of the measurement light 12, the spectra of the four samples 2-1 to 2-4 can be measured simultaneously. However, in this case, the baseline is 2-1 for each sample.
It is necessary to measure at positions ~2-4. FIG. 8 shows an example of a spectrum measured in this manner.

In the above embodiment, four samples are measured at the same time, but when measuring another number of samples at the same time, the number of samples arranged is matched with the number of reflecting mirrors and optical fiber input ends.

Further, in the above embodiment, the reflecting mirror 6- of the measurement light switching mechanism is
Although plane reflecting mirrors are used as 1 to 6-4, concave reflecting mirrors may also be used. When using a concave reflector,
As shown in FIG. 9, the reflection ji 6 a -1~6a
- Narrow the width of 4. Accordingly, the width of the photodetector signal becomes narrower as shown in FIG. 10 than that in FIG. 6. Therefore, the width of the rotation detection signal from the rotation detector 14 is also narrowed.

By using the concave reflection tf16a-1 to 6a-4, the measurement light 12 can be focused on the center of the samples 2-1 to 2-4, and the amount of the samples 2-1 to 2-4 can be reduced. I can do it.

FIG. 11 shows yet another embodiment.

In the embodiment shown in FIG. 1, the measurement light 12 that has passed through the samples 2-1 to 2-4 is guided to the photodetector 18 using optical fibers 16-1 to 16-4, but in the embodiment shown in FIG. Now, sample 2-
On the side that receives the measurement light 12 that has passed through the measuring beams 1 to 2-4, there are also mirrors 26-1 to 26-4 attached to the same rotating shaft 24 as on the incident side. belt 1
The measurement light 12 is rotated synchronously by a motor 8 via a mirror 26-1, passes through a sample 2-1, is reflected by a reflector 26-1, and is guided to a photodetector 18. The measurement light 12 reflected by the reflection mirror 6-2 passes through the sample 2-2, is reflected by the reflection mirror 26-2, and is guided to the photodetector 18, and the measurement light 12 reflected by the reflection mirror 6-3 is It passes through the sample 2-3, is reflected by the reflecting mirror 26-3, and is guided to the photodetector 18.
The measurement light 12 reflected by the reflecting mirror 6-4 passes through the sample 2-4, is reflected by the reflecting mirror 26-4, and is guided to the photodetector 18.

FIG. 12 shows another example of the data processing section.

A sample hold circuit 28 is connected to the output line of the photodetector 18.
Connect. A photodetector signal of a certain sample is held by the rotation detection signal of the rotation detector 14, and the signal is converted into a digital signal by the A/D conversion circuit 30 and input into the computer 34 via the input port 32. On the other hand, the rotation detection signal of the one-rotation detector 14 is also taken into the computer 34 via the input port 36, and the photodetector signal is discriminated for each sample using the rotation detection signal.
-4 and are stored.

(Effects of the Invention) In the present invention, instead of dispersing the measurement light onto a plurality of samples arranged, the measurement light switching mechanism sequentially switches the measurement light and makes it incident on the sample, so there is little loss of optical energy of the measurement light and high S. /N ratio.

In the measurement light switching mechanism, the measurement light is switched by rotating a reflector attached to the rotating shaft, so high-speed switching is possible, and simultaneous measurement of multiple samples is possible, allowing continuous changes in absorbance, etc. be able to measure.

[Brief explanation of the drawing]

FIG. 1 is a schematic plan view showing parts other than the data processing section in one embodiment, FIGS. 2A and 2B are plan views showing the state of the reflecting mirror of the measurement light switching mechanism, and FIG. FIG. 4 is a side view of the reflecting mirror and the rotating shaft viewed from the measurement light incident direction, FIG. 4 is a perspective view showing the reflecting mirror and the rotating shaft, FIG. 5 is a circuit diagram showing an example of the data processing section in one embodiment, and FIG. The figure is a waveform diagram showing the operation of one embodiment, Figures 7 and 8 are waveform diagrams each showing a measurement example using one embodiment, and Figure 9 is a measurement of the reflecting mirror and rotation axis in another embodiment. FIG. 10 is a waveform diagram showing the operation when using the reflecting mirror of FIG. 9, and FIG. 11 is a schematic plan view showing parts other than the data processing section in another embodiment. 12 are block diagrams showing a data processing section in another embodiment. 2-1 to 2-4...Sample, 4,24...
・Rotating shaft, 6-1 to 64, 6a-1 to 6a-4, 26-
1 to 26-4...Reflector, 8...Motor, 12...Measurement light, 14...Rotation detector, 16-1 to 16- 4...Optical fiber, 1
8...Photodetector, 20...Demultiplexer, 22-1 to 22-4.28...Sample and hold circuit, 34...Computer, 38
-1 to 38-4...Memory. Patent applicant: Shimadzu Corporation

Claims (1)

[Claims] (1) A measurement light switching mechanism that sequentially switches measurement light to make it incident on a plurality of fixedly arranged samples, a light receiving section that receives the measurement light that has passed through the sample with a single photodetector, and the measurement The measurement light switching mechanism includes a rotation detection section that detects the switching position of the light switching mechanism, and a data processing section that processes the measurement signal of the light receiving section based on the detection signal of the rotation detection section. A plurality of reflecting mirrors corresponding to the rotation axis are attached to the rotation axis, and each reflection mirror has a different position in the rotation axis direction, is tilted with respect to the rotation axis direction, and has an equal rotation with respect to the incident direction of the measurement light. A spectrophotometer occupies a corner.