JPH02262034A - Method and apparatus for detecting bubble in liquid sample - Google Patents

Abstract

PURPOSE:To prevent errors in distributing amounts caused by the formation of bubbles and to make analysis and inspection highly accurate by detecting bubbles when the bubbles are formed by the mixing of air when a chip is inputted into a sample in an automatic distributing apparatus which is used for inspecting the samples such as serum, urine, reagent and the like, and stopping the analysis and the inspection of the chip. CONSTITUTION:Near infrared-rays from a near infrared-ray emitting diode 16 is condensed to a certain size in the axial direction of a chip 10 by using a lens 18 and a circular cylinder lens 20. Thus the near infrared rays are inputted. Only the light which has transmitted through this position is inputted into a photodetector 26 through an optical filter 24. At this time, the vacant chip 10 is moved in the direction of an arrow at a constant speed. The amount of the near infrared-rays transmitted through this position is detected with the photodetector 26. The result is stored in a first level memory 34. Then, the chip 10 in which liquid sample is inputted to as not to form bubbles is further moved. The light is detected with the photodetector 26, and the result is stored in a second level memory 36. The amounts of the transmitted light rays stored in the memories 34 and 36 are subtracted in a subtractor 38. The result is compared with a reference value in a reference value memory 42 in a comparator circuit 44.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to the analysis and testing of liquid samples such as serum, urine, and reagents (
The present invention relates to a method and device for detecting air bubbles in a liquid sample in an automatic dispensing device used for sample testing.

[Conventional technology]

In conventional automatic dispensing devices of this type, a liquid sample (hereinafter referred to as a specimen) is placed in a container of a desired shape (hereinafter referred to as a chip) for analysis and inspection.

[Problem to be solved by the invention]

According to the above-mentioned conventional automatic dispensing device, even if air bubbles (size of about 0.5 to 1 mm) occur in the sample placed in the chip,
No consideration was given to detecting these bubbles. Therefore, even if bubbles are generated due to air intrusion when placing a sample into the chip, the sample is dispensed as is, resulting in an error in the amount dispensed. This error has a considerable effect on the analytical value (at the time of testing), and the problem is that the effect is particularly large when dispensing a small amount of sample.

OBJECTS OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and its purpose is to provide a method and apparatus for detecting air bubbles generated in a specimen.

[Means to solve the problem]

In order to achieve the above object, the method for detecting air bubbles in a sample according to the invention described in claim (1) is such that near-infrared light generated from a light emitting body is formed into a beam, and a chip through which this near-infrared light is transmitted is provided. A specimen is placed in the chip, and the chip is moved in one direction at a constant speed so as to intersect with the beam-shaped near-infrared light, and the amount of transmitted light of the near-infrared light transmitted through the chip is compared with the sky whose ΔPI is fixed in advance. Subtract the amount of transmitted light of near-infrared light that has passed through the chip, and this subtracted value is the amount of transmitted light of near-infrared light that has passed through the empty chip in advance and the amount of transmitted light of the near-infrared light that has passed through the empty chip. By being smaller than the standard value determined based on the subtraction value from the transmitted light amount level of near-infrared light transmitted through the
It is characterized by determining whether bubbles have occurred.

The apparatus for detecting air bubbles in a specimen according to the invention described in claim (2) includes: an optical system that converts near-infrared light generated from a light-emitting body into a beam; a chip through which the near-infrared light passes; a chip moving means that moves the chip containing a sample in one direction at a constant speed while crossing the beam of near-infrared light; and a photodetector that detects the near-infrared light that has passed through the chip.
A first. a second integrating circuit; and the first integrating circuit. The first one stores the level of the amount of transmitted light smoothed by the second integrating circuit. Second
the transmitted light amount level memory, the transmitted light amount level of near-infrared light transmitted through the empty chip stored in the first transmitted light amount level memory, and the sample memorized in the second transmitted light amount level memory. a subtracter for subtracting the transmitted light level of the near-infrared light transmitted through the empty chip; Compare the reference value determined based on the subtracted value from the transmitted light amount level of near-infrared light transmitted through the chip containing the sample with the memory value of the reference value memory, and if the former is smaller than the latter, bubble generation is detected. The present invention is characterized by comprising a comparison circuit that outputs a discrimination signal.

[Effect]

As described above, according to the method for detecting air bubbles in a sample according to the invention described in claim (1), when air bubbles are detected, measures such as not dispensing or redispensing are taken to stabilize the sample. analysis and inspection.

Further, according to the device for detecting air bubbles in a specimen according to the invention as set forth in claim (2), air bubbles mixed in a specimen can be detected with high accuracy with a simple configuration.

〔Example〕

FIG. 1 is a schematic diagram of an apparatus suitable for implementing the method of detecting air bubbles in a sample according to the present invention, FIG. 2 is a plan view of a part of the apparatus, and FIG. FIG. 3 is a characteristic diagram of the transmitted light amount level with respect to the beam position on the intersecting chip 10. FIG.

In FIGS. 1 and 2, a chip 10 that transmits near-infrared rays is made of an optically transparent or translucent material such as plastic, contains a sample (for example, serum) 12, and has a chip moving means 14. is sent in one direction at a constant speed, in the illustrated example upward in the direction of the arrow.

The near-infrared light emitting diode 16 as a light emitter is 700
It emits near-infrared light having a wavelength of nm to 11,000 nm, and this near-infrared light is passed through an optical system of a lens 18 and a cylindrical lens 20 to cross the chip 10 with a certain width and a certain thickness. beam 22.

The beam 22 that has passed through the chip 10 passes through an optical filter 24 that transmits only light with wavelengths in the near-infrared region, and passes through a photodetector 26.
leading to.

The output side of the photodetector 26 is connected to the first. A second integration circuit 30.32 is connected, and first and second level memories 34.36 are provided on the output side of each integration circuit 30.32. The output of 34.36 is subtracted by a subtracter 38.

A reference value memory 42 for storing a reference value determined based on the output of the subtracter 38 is connected to the output side of the subtracter 38 via a changeover switch 40. A comparison circuit 44 is connected to compare the reference value memory output and the subtracter output to determine the presence or absence of bubbles.

Next, the bubble detection method of the present invention will be specifically explained.

The near-infrared light emitted from the near-infrared starter □ photodiode 16 is converted into a parallel beam by the lens 18, and further condensed to a certain size in the axial direction of the chip 10 by the cylindrical lens 20. It will be done. The size of this constriction is determined by the minimum volume of bubbles generated in the sample to be detected.

In addition, the beam width in the direction perpendicular to the axis of the chip 10 is larger than the width determined by the positional intersection of the chips, so even if the positional accuracy of the tip of the chip 10 is poor, the beam 22 is always connected to the chip 1.
It is designed to emit 0.

The light transmitted through the chip 10 passes through an optical filter 24,
Detection is performed in such a way that light in the visible range such as other illumination light does not enter the photodetector 26.

First, the changeover switch 28 is turned on to the contact A1, and the changeover switch 40 is turned on to the contact A, respectively. In this state, when the empty chip 10 is moved from the illustrated position at a constant speed in the direction of the arrow by the chip moving means 14, the amount of near-infrared light transmitted through the chip 10 is detected by the photodetector 26. , is input to the first integrating circuit 30 via the changeover switch 28, is smoothed as the transmitted light amount level a shown in FIG. 3, and is stored in the first level memory 34.

Next, the changeover switch 28 is switched to contact B, and the chip 10 containing the liquid sample in a manner that no bubbles are generated is moved by the chip moving means 14 from the position shown in the figure at a constant speed in the direction of the arrow. At this time, the near-infrared light transmitted through the chip 10 is detected by the photodetector 26, is inputted to the second integrating circuit 32 via the changeover switch 28, and is smoothed as the transmitted light amount level b shown in FIG. and stored in the second level memory 36.

Next, the level outputs a and b of the first and second level memories 34 and 36 are subtracted by the subtracter 38, and the reference value d determined based on the subtracted value C is stored in the biquadratic value memory 42. The above is the reference value determination operation performed prior to the bubble detection operation.

Next, the changeover switch 28 and the changeover switch 40 are respectively switched to contact B to perform an actual bubble detection operation. That is, as described above, the chip 10 containing the liquid sample is moved from the illustrated position at a constant speed in the direction of the arrow by the chip moving means 14, and the amount of transmitted light transmitted through the chip 10 during this movement is detected by the photodetector 26. do.

Then, the detection signal from the photodetector 26 is smoothed by the second integrating circuit 32 via the changeover switch 28, and is stored in the second level memory 36. Next, the subtractor 38 subtracts the transmitted light amount level of the empty container stored in the first level memory 34 and the transmitted light amount level stored in the second level memory 36, and this subtracted value C' and the transmitted light amount level stored in the second level memory 36 are subtracted. The comparison circuit 44 compares the reference value d stored in the reference value memory 42 with the reference value d.
Compare with.

In this case, if there are air bubbles in the liquid sample in the chip 10, the subtraction value C' becomes smaller than the reference value d. You can tell that bubbles have formed in the sample.

Note that the reason why the transmitted light amount level increases with time is because the shape of the chip 10 is tapered.

〔Effect of the invention〕

As described above, according to the method for detecting air bubbles in a liquid sample of the present invention, when air bubbles are generated due to air being mixed in when a sample is put into a chip, the air bubbles are detected and the chip is analyzed.
Since the inspection can be omitted, errors in the dispensed amount due to the generation of air bubbles can be prevented. As a result, there is an effect that stable analytical tests can be performed with high precision.

Further, this bubble detection device has a simple configuration including an optical system for irradiating a near-infrared light beam, a photoelectric conversion circuit, and a chip moving means, and can be obtained at low cost.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of an apparatus suitable for carrying out the method of detecting bubbles in a liquid sample according to the present invention, FIG. 2 is a plan view of a part thereof, and FIG. FIG. 3 is a characteristic diagram of the transmitted light amount level with respect to the beam position on the chip. 10... Chip (container) 12... Specimen (liquid sample) 14... Chip moving means 16... Near-infrared light emitting diode 18. 20... Lens 22... Beam 26... Photodetector 30...First integrating circuit 32...Second integrating circuit 34...First level memory 36...Second level memory 38...Subtractor 42...Reference Value memory 44...comparison circuit.

Claims (2)

[Claims] (1) Near-infrared light generated from a light emitter is made into a beam, a liquid sample is placed in a container through which this near-infrared light passes, and the container is made to intersect with the near-infrared light beam at a constant speed. The amount of near-infrared light transmitted through this container is subtracted from the amount of near-infrared light transmitted through an empty container that has been measured and stored in advance, and this subtraction value is A reference value determined in advance based on the subtraction value between the level of transmitted light of near-infrared light transmitted through an empty container and the level of transmitted light of near-infrared light transmitted through a container containing a liquid sample without bubbles. 1. A method for detecting air bubbles in a liquid sample, characterized in that the occurrence of air bubbles is determined based on the fact that the air bubbles are smaller. (2) An optical system that forms a beam of near-infrared light generated from a light-emitting body, a container through which this near-infrared light passes, and a container containing a liquid sample that intersects with the near-infrared light beam. a container moving means for moving the container in one direction at a constant speed; a photodetector for detecting the near-infrared light transmitted through the container; and a photodetector connected to the output side of the photodetector via a changeover switch. 1. a second integrating circuit; first and second transmitted light level memories that store transmitted light level levels smoothed by the first and second integrating circuits; and the first transmitted light level memory. Subtracting the transmitted light amount level of the near-infrared light transmitted through the memorized empty container and the transmitted light amount level of the near-infrared light transmitted through the container containing the liquid sample stored in the second transmitted light amount level memory. and a subtractor that calculates the subtracted value of the subtractor from the level of transmitted light of near-infrared light that has passed through an empty container and the amount of transmitted light of near-infrared light that has passed through a container containing a liquid sample in a state where no bubbles are generated. A comparison circuit that compares the reference value determined based on the value subtracted from the level with the memory value of the stored reference value memory and outputs a determination signal of bubble generation when the former is smaller than the latter. A device for detecting air bubbles in liquid samples.