JPH0134335B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a sample collection device such as a spectrophotometer,
In particular, the present invention relates to a device for collecting and measuring a small amount of sample liquid.

For example, clinical serum analyzers, clinical Na, K,
Flame photometers for Li analysis, atomic absorption spectrometers using graphite atomizers as analysis parts, etc.
A minute amount of sample liquid of ~50μ is collected and introduced using an automatic pipette or microsyringe. When collecting such a small amount of sample liquid, reproducibility is generally low, and errors in analytical values depend solely on measurement errors of pipettes or microsyringes. In order to improve this problem, significant advances in the sample measuring device described above and careful operation by the operator are required, which is impossible to achieve at the current stage.

FIG. 1 is an explanatory diagram of a conventional sample liquid sampling and measuring device, and this figure shows the case where a sample liquid is introduced into a graphite atomizer. The tip of a liquid suction tube 2 is inserted into the sample liquid contained in the sample container 1, and the liquid suction tube 2 is connected to a microsyringe 4 via a three-way switch valve 3. In addition, since a liquid injection pipe 6 is connected to the right side of the switching valve 3, when the plunger 5 of the syringe 4 is raised with the rotation of the eccentric cam 9, the sample liquid is automatically sucked, and the switching valve 3 is moved to the right. When the eccentric cam is rotated by 90 degrees and the plunger 5 is pushed, a small amount of the sample liquid 8 can be automatically introduced into the analysis section 7 through the liquid injection tube 6.

However, with such a micro-inhalation/dispensing device using a syringe, there is no large measurement error like when an unskilled person uses a micropipette to measure the amount, but it is difficult to improve the measurement accuracy beyond a certain level. Moreover, when the amount to be collected changes, it is necessary to replace the eccentric cam 9 or change the syringe 4, which has the problem of requiring time.

The purpose of the present invention is to provide a device for collecting and measuring a small amount of sample liquid, which can significantly reduce analysis errors by making small improvements to the conventional device. A device for collecting and measuring a small amount of sample liquid, which sucks the sample liquid into a microsyringe through a liquid suction pipe through a switching valve, and injects the sample liquid sucked into the microsyringe from a liquid injection pipe by switching the switching valve. The liquid injection tube is a thin tube made of a transparent material and has an inner diameter of a constant size, and the liquid surface has a light emitting element portion and an array detector facing each other through the thin tube at a plurality of locations in the longitudinal direction of the thin tube. This is due to the installation of a detector.

Generally, to determine the concentration of a component in a sample liquid, a method is used in which a sample of a certain volume or weight is weighed and the amount of solute therein is measured. for example
10μ and 100μ are collected using the syringe 4, and the measurement accuracy directly affects the measurement accuracy of the component concentration.

When the concentration of the component to be measured in the sample liquid is C, the following equation holds true.

C=M/N (1) Here, M is the weight of the solute in the weighed sample liquid, and N is the weight of the sample liquid, so the accuracy with which the sample liquid is collected directly affects the analysis accuracy. Factors that reduce reproducibility in each sample weighing operation include:
These include wetting or adhesion of droplets on the end surface of the liquid transport tube, insufficient mechanical precision of the eccentric cam, airtight leakage of the syringe, and liquid pooling at the connection between the syringe and the liquid transport pipe. The present invention improves analysis accuracy by correcting these measurement errors even if they remain, and will be explained below with reference to the drawings.

FIG. 2 is an explanatory diagram of a sample liquid sampling and measuring device according to an embodiment of the present invention, in which the same parts as in FIG. 1 are given the same reference numerals. In this case, liquid level detectors 10 and 11 are attached to a plurality of locations on the liquid injection pipe 6 and connected to the signal processing section 12. The liquid injection tube 6 is a thin tube that is transparent and has a uniform inner diameter, such as a corrosion-resistant synthetic resin thin tube, and the volume between the two liquid level detectors 10 and 11 is determined to be the amount of sample required for analysis. There is.

FIG. 3 is an enlarged sectional view of the measuring section shown in FIG. 2, in which a first liquid level detector 10 and a second liquid level detector 11 are attached to the liquid injection tube 6 made of a transparent synthetic resin thin tube. be. The capacitance between the two is set to be approximately 10μ, for example.

FIG. 4 is a cross-sectional view of the first liquid level detector shown in FIG. The arranged array detector is shown. The small luminous flux generated from each element of the light emitting element section 10a is directed toward the elements of each array detector 10b facing each other, but since the reflection loss between the wall surface of the liquid injection tube 6 and the air 13 is large above the liquid level 14a. The transmitted light is significantly reduced. This liquid level detector 10
Since each element is densely arranged at intervals of 15 to 30 μm, the position of the liquid level 14a can be accurately determined.

The same applies to the second photodetector 11, but in this case, if the position of the liquid level 14b is made to match the reference position, the second photodetector 11b can be made small with a relatively small number of elements. The light emitting element section can be formed using a small array detector 11b. In addition, since the liquid injection tube 6 uses a water-repellent alloy resin tube, it does not stick to the tube wall and remain.
All sample liquids can be introduced.

The operation of the micro-volume sampling and measuring device configured as described above will be explained with reference to FIG. When the switching valve 3 is in communication with the liquid injection pipe 6, the plunger 4 is slightly raised to draw air into the liquid injection pipe 6. next,
The switching valve 3 is rotated 90 degrees counterclockwise to the state shown in FIG. 2, and the plunger 5 is raised to aspirate a predetermined amount of sample liquid to fill the microsyringe 4 and the switching valve 3 with the sample liquid.

After a predetermined amount of sample liquid 8 has been collected in this manner, the switching valve 3 is rotated clockwise by 90 degrees, and the plunger 5 is gradually pushed down. Therefore, the sample liquid 8 in the switching valve 3 and the syringe 4 descends in the liquid injection tube 6, and when the state approaches the state shown in FIG. 3, the movement of the plunger 5 is temporarily stopped. After that, the volume of the air storage part of the liquid injection tube 6 is slightly changed using a screw device installed at the top of the elastic liquid injection tube 6 made of synthetic resin, and the lower end of the sample liquid 8 is connected to the second photodetector. 11 to match the position of the reference liquid level 14b. At this time, the first
Since we can know the distance l between the position of the linear array that detected the liquid level 14a of the liquid level detector 10 and the reference liquid level 14b, we can multiply this by the cross-sectional area πd ² /4 due to the inner diameter d of the liquid injection tube 6. If so, the amount of sample solution 8 is known,
This sample amount data is output to the signal processing section 12 and stored. That is, since the amount of introduced sample liquid corresponding to the denominator N in equation (1) can be accurately determined, the analytical accuracy of the solute concentration in the sample liquid 8 obtained as an analysis result is improved.

Further, the shape of the cam 9 is formed to enable the above operations, and the series of sample liquid sampling and measuring operations described above are automatically performed according to a set program. In the above embodiment, the second liquid level detector 11 is simplified in size, but if the same one as the first liquid level detector 10 is used, the lower end liquid level 1
There is no need to regulate the position of 4b, no need for fine adjustment of the liquid level position, and all operations can be automated.

The micro sample liquid collection and measuring device of this embodiment includes a syringe for collecting a sample liquid and a liquid injection tube made of a transparent thin tube for transferring the collected sample liquid to an analysis section, and the liquid injection tube has a predetermined volume. The liquid level position is detected by using a light emitting element section in which a large number of small light emitting elements are arranged linearly in two locations, and an array detector in which a large number of semiconductor photodetectors are arranged in a linear manner facing the light emitting element section. Therefore, a small amount of liquid can be accurately and automatically measured. Therefore, it is possible to obtain the effect that the true amount of sampled liquid can be known and the accuracy of analysis can be greatly improved.

In the above embodiment, a pair of liquid level detectors are installed in the liquid injection tube 6 to measure a fixed amount of sample liquid, but if the number of liquid level detectors is further increased, different amounts of sample liquid can be measured. It can be collected and weighed. Since the amount of movement of the plunger 5 at this time is different, an appropriate eccentric cam 9 and program are used.

The sampling and measuring device for a small amount of sample liquid of the present invention uses a liquid injection tube as a transparent thin tube, and has a light emitting element part in which a large number of light emitting elements are arranged in two places above and below the light emitting element part, and an array detector having a row of photodetecting elements arranged in opposition thereto. A relatively simple improvement in processing the signal can have the effect of significantly reducing analytical errors.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of a conventional sample liquid collection/measuring device, Fig. 2 is an explanatory diagram of a trace sample liquid collection/measuring device which is an embodiment of the present invention, and Fig. 3 is an enlarged view of the measuring section in Fig. 2. 4 is a cross-sectional view of the first photodetector of FIG. 3; FIG. DESCRIPTION OF SYMBOLS 1...Sample container, 2...Liquid suction pipe, 3...Switching valve, 4...Microsyringe, 5...Plunger, 6...
...Liquid injection tube, 7...Analysis section, 8...Sample liquid, 9...
...Eccentric cam, 10...First liquid level detector, 10a
...Light emitting element section, 10b...Array detector, 1
1... Second liquid level detector, 12... Signal processing unit,
13...Air, 14...Liquid level.

Claims (1)

[Scope of Claims] 1. A sample liquid contained in a sample container is aspirated into a microsyringe through a switching valve through a liquid suction tube, and the sample liquid sucked into the microsyringe is injected into a liquid by switching the switching valve. In an apparatus for collecting and measuring a small amount of sample liquid injected from an injection tube, the liquid injection tube is a thin tube made of a transparent material and having an inner diameter of a certain size, and the thin tube is opposed to each other at multiple points in the longitudinal direction of the thin tube through the thin tube. 1. An apparatus for collecting and measuring a small amount of a sample liquid, comprising a liquid level detector having a light emitting element section and an array detector. 2. The liquid level detector has a light emitting element section in which a large number of small light emitting elements are arranged in series, and an array detector in which a large number of small photoelectric detection elements are arranged in series and facing the light emitting element section. 2. The sample liquid sampling and measuring device according to claim 1, which is a permeation position detector.