JP2000266768A - Automatic analyzer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent hovering of a dispensing mechanism, when requiring liquid level detection of a test body, and to shorten a time required for a dispensing operation. SOLUTION: This device 1 has a multi-electrode electrostatic capacity sensor 6, a dispensing mechanism 5 where a liquid level detector 18 is loaded, a transmission part 17, and a control part 2. Information of an approximate height of a liquid level of a test body, foam and splash, and of an electrostatic capacity on charged parts on the inner and outer surfaces of a test body vessel is obtained by the multi-electrode electrostatic capacity sensor 6, and thereby control of a lowering operation of the dispensing mechanism 5 is executed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic analyzer, and more particularly to an automatic analyzer for controlling a lowering operation of a dispensing mechanism.

[0002]

2. Description of the Related Art A dispensing probe provided in a conventional automatic analyzer is a detector for detecting contact with a sample, an amount of the sample, and a liquid level of the sample. And, utilizing the fact that the conductivity is very different, install a detector to detect capacitance or impedance, and dispensing probe on the liquid surface of the sample while lowering the dispensing probe. Touches, the capacitance being detected, or
The impedance was changed, and the change was used as a trigger to stop the lowering of the dispensing probe. There is also known a method of transmitting light having a wavelength absorbed by a sample from the side of a container and measuring the transmitted light intensity from the other side to detect the liquid level of the sample.

[0003]

In the case where a bubble, a droplet, or a film-like liquid is adhered above the liquid surface in the sample container, or when a charged portion exists, the conventional electrostatic In a dispensing probe equipped with a capacitance type liquid level detector, when the probe tip comes into contact with bubbles, droplets, or a film-like liquid, the capacitance during detection greatly changes, and the original sample liquid is detected. If a position other than the surface is incorrectly determined to be the liquid level, or if the sample container or sample is charged and discharge occurs between the tip of the dispensing probe and the charged part, the voltage change due to the discharge will occur. Is incorrectly determined to be a liquid level detection signal, causing a phenomenon called hovering in which the dispensing probe stops descending, and it may not be possible to aspirate the amount of sample necessary for analysis.

Further, in order to prevent hovering, a method is employed in which the liquid level is determined by detecting the liquid level once and then checking the signal of the sensor again during the dispensing probe lowering operation. May be used.

However, in this method, since the dispensing probe continues to descend between the first detection and the second detection, it is possible to stop the lowering operation at the original liquid level to be stopped. As a result, the amount of the suction nozzle tip that enters the sample increases, and the area where the tip of the dispensing probe is contaminated with the sample increases.

An object of the present invention is to prevent the above-mentioned hovering and to lower the dispensing mechanism at a high speed.

[0007]

Means for Solving the Problems In an automatic analyzer,
By installing a plurality of opposed electrodes in the storage unit around the sample container, the capacitance between the installed plurality of opposed electrodes is detected. The injection mechanism is moved down at a high speed, and high-capacity parts such as bubbles, droplets, liquid in the form of a film, and charged parts are found in the sample container, and hovering is performed using the detected capacitance information. Dispensing control section for performing a dispensing operation that does not cause the

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to examples.

[Embodiment 1] FIG. 1 is a schematic configuration diagram of an embodiment of an automatic analyzer according to the present invention.

In FIG. 1, an automatic analyzer 1 comprises a control unit 2, a storage unit 3, an analysis unit 4, a dispensing mechanism 5, and a multi-electrode capacitance sensor 6. The control unit 2 includes a dispensing control unit 7 for controlling the detailed operation of the dispensing mechanism, and a unit for controlling the operation of each unit by an electronic circuit and a storage device for performing detailed operation control of each unit. Overall control of operation.

The storage section 3 is a section for holding a test tube 10 containing the sample 9, and the dispensing mechanism 5 is used to analyze the sample 9 from the test tube 10 held in the storage section 3 for analysis. This is a mechanism that sucks a large amount and discharges it into the reaction vessel 11 of the analysis unit 4.
The sample 9 is aspirated and ejected.

Further, the dispensing mechanism 5 is equipped with a liquid level detector 18 for generating a signal indicating that the liquid has come into contact with the liquid surface when a change occurs in the capacitance during detection. When a signal indicating that the liquid surface has come into contact with the liquid surface is generated from the liquid level detector 18 during the lowering operation, the dispensing mechanism 5 immediately stops lowering. The analysis unit 4 mixes the sample 9 and the reagent in the reaction container 11 of the analysis unit and reacts them, and then performs the composition analysis by the spectroscope 12.

The multi-electrode capacitance sensor 6 includes a capacitance detection electrode array 13, a controller 14, and a multiplexer 1.
5, a capacitance detection unit 16 and a transmission unit 17. The capacitance detection electrode array 13 is formed by arranging a plurality of metal electrodes in an array. The smaller the distance between the electrodes, the more points for detecting the capacitance.

The capacitance detection electrode array 13, which is an assembly of electrodes, is arranged at a portion where the test tube 10 is placed in the storage section 3 so that the electrodes are arranged in an array in the height direction of the test tube 10. The two capacitance detection electrode arrays 13 are arranged to face each other so as to sandwich the test tube 10. A signal line is output from each electrode and connected to the multiplexer 15.

The multiplexer 15 includes a controller 14
, Any one, a plurality, or all of the electrodes in the capacitance detection electrode array 13 and any one, a plurality, or all of the electrodes in the capacitance detection electrode array 13 opposed thereto. And the connection with the capacitance detection unit 16 is performed.

The capacitance detecting section 16 includes a controller 14
Switches the multiplexer 15 one after another to detect the capacitance between the connected electrodes.
The capacitance in the diameter direction of 0 is checked in the height direction of the test tube 10.

The transmission section 17 transmits the obtained information on the capacitance to the dispensing control section 7. As shown in FIG. 2, the capacitance information indicates that the liquid has a high dielectric constant with respect to the gas, so that the capacitance up to the liquid level of the specimen 9 is high, and the capacitance of a portion where the specimen 9 is not contained. Is detected lower.

The dispensing control section 7 lowers the dispensing mechanism 5 at high speed to the vicinity of the estimated liquid level from the detected capacitance information, and then the liquid level detector 18 changes the liquid level. After detecting the liquid level, the dispensing mechanism 5 is stopped, and the sample 9 is aspirated.

When bubbles 19 and droplets 20 are present in the test tube 10, the detected value between the electrodes to be measured depends on the influence of the bubbles 2.
1, Capacitance in the absence of foam 2
Utilizing the fact that the size is slightly larger than that of No. 3, the dispensing control unit 7 estimates the location where the bubbles 19 and the droplets 20 are present, and ignores the bubbles 19 and the droplets 20 that cause hovering, and dispenses the dispensing mechanism. 5 is performed.

[Embodiment 2] FIG. 3 shows an improvement of a method of arranging a multi-electrode capacitance sensor according to the present invention. A plurality of capacitance detection electrode arrays 13 are additionally arranged.

[Embodiment 3] FIG. 4 is an improved plan of the detection method of the multi-electrode capacitance sensor according to the present invention. The rotation for rotating the test tube 10 in the storage section 3 of the automatic analyzer 1 in FIG. A mechanism 25 is provided.

[0022]

According to the first embodiment of the present invention, when a multi-electrode capacitance sensor installed for the purpose of preventing hovering occurring when dispensing a sample is used, the capacitance of the multi-electrode sensor is reduced. From the distribution, it is possible to estimate the approximate height of the liquid surface, the bubbles attached to the inner surface of the sample container, the sample droplets, or the strong charged portions on the inner and outer surfaces of the container.

The suction unit is used to prevent contamination of the dispensing mechanism that actually performs the dispensing operation by applying the obtained information on the capacitance to the control of the dispensing operation. A liquid level detection sensor that detects the liquid level of the sample, provided so as to reduce the area where the nozzle contacts the sample,
It is possible to prevent erroneous detection of a liquid level in a portion having a high capacitance value such as a foam, a sample splash, or a strong charged portion on the inner and outer surfaces of the container, which can cause hovering, and can be estimated in advance. The dispensing mechanism can be lowered at high speed to near the original liquid level.

According to the second embodiment, obtaining capacitance information from a plurality of multi-electrode capacitance sensors requires a liquid surface generated by surface tension as compared with a case where only one pair of multi-electrode capacitance sensors is arranged. It is possible to average information on a small difference in height and a localized portion having a high capacitance such as a bubble or a droplet, thereby reducing the influence of the localized capacitance.

According to the third embodiment, the same effect as that of the second embodiment can be obtained by rotating the sample container by the rotating mechanism.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of one embodiment of an automatic analyzer according to the present invention.

FIG. 2 is a conceptual diagram of a capacitance value obtained from an electrode capacitance sensor according to the present invention.

FIG. 3 is a view showing an improvement of an arrangement method of a multi-electrode capacitance sensor according to the present invention.

FIG. 4 is a diagram showing an improved proposal of a capacitance detection method of a multi-electrode capacitance sensor according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Automatic analyzer, 2 ... Control part, 3 ... Storage part, 4 ... Analyzing part, 5 ... Dispensing mechanism, 6 ... Multi-electrode capacitance sensor, 7 ... Dispensing control part, 9 ... Sample, 10 ... Test Tube, 11 ... reaction vessel,
12: spectroscope, 13: capacitance detection electrode array, 14:
Controller, 15 Multiplexer, 16 Capacitance detection unit, 17 Transmission unit, 18 Liquid level detector, 19 Bubbles,
20: splash, 21: effect of foam, 22: effect of splash, 23
... capacitance in the absence of foam, 24 ... capacitance in the presence of foam, 25 ... rotation mechanism.

Claims (1)

[Claims] 1. A control section for controlling the operation of the apparatus and processing information necessary for the operation of the apparatus, and a sample such as a test tube for storing and storing the sample before and after the analysis. Equipped with a storage unit that holds multiple containers and a dispensing probe that aspirates the sample, performs ascent and descent, and aspirates the amount of sample required for analysis from the sample container held in the sample storage unit An automatic dispensing mechanism that has a dispensing mechanism that discharges the sample aspirated into the container of the analyzer, an analyzer that analyzes the composition of the sample, and a container that mixes and reacts the sample with the reagents and the like used in the analysis. In the analyzer, a multi-electrode capacitance sensor in which a plurality of electrodes are arranged around the sample container is provided in the storage unit, and any pair of at least two or more electrodes sandwiching a space where capacitance is to be detected from among the plurality of arranged electrodes. Controller to select the electrodes of the A capacitance detecting unit that detects the capacitance value between the electrodes selected by the method and obtains information on the capacitance, and dispensing that controls a dispensing operation based on the obtained information on the capacitance between the electrodes. An automatic analyzer including a control unit and a transmission unit that transmits capacitance information to a dispensing control unit.