JPH05281241A - Automatic pipetter of analyzing apparatus - Google Patents

Abstract

PURPOSE:To detect a liquid surface accurately without bringing a part other than a tip into contact with a sample and others and further to realize other functions. CONSTITUTION:An impulser 30 generating vibration in a pipet 2 and a pickup 32 detecting the vibration are fitted on the pipet 2. A detection signal of the pickup 32 is amplified by an amplifier 34 and then a vibration frequency is selected by band-pass filters 36a, 36b, 36c,... being set respectively for frequencies such as the vibration frequency for detecting the presence or absence of a tip 4, the vibration frequency for detecting that a state of fit of the tip is imperfect, etc. A signal of each selected frequency is turned into a DC signal by AC-DC converters 38a, 38b, 38c,... and this signal is converted into a digital signal by an A/D converter 40 and taken in by a computer. The computer realizes functions of detection of the presence or absence of the tip, detection of the state of fit, detection of a liquid surface, etc., from a signal at each frequency.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic dispenser for dispensing a sample or the like (collectively referred to as a sample and a reagent) to a reaction container in an analyzer such as an automatic biochemical analyzer. The present invention relates to an automatic pipetting device which dislikes nation and attaches a disposable tip to the tip of a pipette to perform a pipetting operation.

[0002]

2. Description of the Related Art An automatic pipetting apparatus is equipped with a pipette for sucking and discharging a sample or the like, and a liquid level sensor for detecting that the pipette comes into contact with the liquid surface. The liquid level sensor detects that the tip of the pipette has reached the liquid surface, and then the pipette is immersed in the sample or the like to a predetermined depth, and then the sample is sucked. As the liquid level sensor, there are used a type in which the sensor electrode is in contact with the liquid level for detection and a type in which the sensor electrode is in non-contact for detecting the liquid level. Examples of methods that contact the liquid surface include those that measure the electrical conductivity between the pipette and the sensor electrode, those that measure the electrical capacity, those that have a thermometer and heater, and that judge from the cooling effect. Invented. As a method of detecting the liquid surface without contact, a pressure detecting means is provided between the pipette and the pump, and air is ejected or sucked from the pipette, depending on whether the pipette is in the air or in contact with the liquid surface. The liquid level is detected from the change in pressure (see Japanese Patent Laid-Open Nos. 2-196964 and 2-243960).

[0003]

The liquid level sensor in which the liquid level sensor comes into contact with the liquid level of a sample or the like cannot be used in applications where even a very small amount of contamination is a problem. In the non-contact method of detecting the liquid level, a pump for sucking and discharging the sample, etc., which is generally a plunger pump, is used for discharging and aspirating air from the pipette. If so, it is necessary to operate the plunger at the same time as liquid level detection, but since the position of the plunger at the time of liquid level detection cannot be controlled, the suction and discharge of the sample etc. will be limited, and Becomes complicated or the required time increases.

The above-mentioned non-contact method can be used for monitoring of dispensing operation, but other than that, for example, confirmation of delicate fitting state of chips, monitoring of injection liquid amount,
It is not possible to realize functions such as agitation of a sample or the like, treatment of droplets, and strengthening of chip fitting. Therefore, the present invention is an automatic pipetting apparatus that attaches a tip to the tip of a pipette and sucks and discharges a sample or the like, while accurately detecting the liquid surface without contacting the portion other than the tip with the sample or the like. It is an object of the present invention to provide an automatic dispensing device having the function of.

[0005]

FIG. 1 illustrates the present invention. A disposable tip 4 is attached to the tip of a pipette 2 for aspirating and discharging a sample or the like, and the tip 4 is immersed in the sample or the like to suck the sample or the like, moves to a reaction container, and is discharged into the reaction container. It The pipette 2 is provided with a vibration generating means 6 for vibrating the pipette 2 and a vibration detecting means 8 for detecting the vibration of the pipette 2, and the chip 4 is placed on the liquid surface of a sample or the like based on the detected vibration frequency and its vibration intensity. A determination unit 10 that detects at least the contact is provided. The determination unit 10 includes a chip presence / absence detection unit 12 that detects the presence / absence of the chip 4, a chip fitting state detection unit 14 that monitors the fitting state of the chip 4, a liquid level detection unit 16 that detects the liquid level of a sample, etc. Is provided with an immersion depth detector 18 for detecting the depth of immersion in the liquid surface.

[0006]

In order to explain the operation of the present invention, the pipette 2 is fixed with the vice 20 as shown in FIG.
The position marked X is hit with an impulse hammer 22 as a vibration generating means, and a pickup sensor as a vibration detecting means is arranged at a position a indicated by a circle in the figure near the portion where the tip 4 of the pipette 2 is fitted. Then, the vibration was detected and the vibration spectrum was measured. Water 24 contained in a container was used instead of the sample or the like.

FIG. 3 shows a signal spectrum of vibration generated by the impulse hammer 22. The horizontal axis represents the frequency expressed in logarithm, and the vertical axis represents the vibration intensity. 4 to 9, the vertical axis represents the relative value obtained by dividing the detected vibration intensity by the vibration intensity by the impulse hammer of FIG. 3, that is, the transfer function.

The output of the pickup sensor when the tip 4 is not attached to the pipette 2 is as shown in FIG. When the chip 4 is properly mounted, the output of the pickup sensor is as shown in FIG. Comparing the spectrum of FIG. 4 and the spectrum of FIG. 5, 232 Hz that was emitted when the chip 4 was not attached
It can be seen that the peak signal of 1 is shifted to 205 Hz by mounting the chip 4 correctly. Therefore, the chip presence / absence detection unit 12 determines that the chip 4 is correctly mounted by detecting that the signal of 205 Hz becomes equal to or higher than a predetermined level. Further, by mounting the chip 4 while vibrating the pipette 2 while the chip 4 is not mounted on the pipette 2, the presence or absence of the chip 4 with respect to the pipette 2 can be monitored by the change of the vibration frequency and the vibration intensity. ..

FIG. 6 shows a vibration spectrum when the chip 4 is mounted, but is not mounted correctly and is mounted in a defective state of wobbling. When the spectrum of FIG. 6 is compared with the spectrum of FIG. 5 when the chip 4 is correctly mounted, a downward peak of 145 Hz is observed when the chip 4 is not correctly mounted. Therefore, the chip fitting state detection unit 14 determines that the chip 4 is not properly mounted by detecting that the 145 Hz signal has become equal to or lower than the predetermined level. In addition, a certain amount of vibration is applied from the vibration generating means, and the vibration frequency and the vibration intensity when the tip 4 is not attached to the pipette 2 and the vibration frequency and the vibration intensity when the tip 4 is attached. The fit of the chips can be monitored. Furthermore, by comparing the vibration frequency and the vibration intensity after a certain period of time, it is possible to monitor whether the fitting state of the chip has changed.

The vibration spectrum when the pipette with the tip 4 mounted is held in the air is shown in FIG. 7 (however, different from FIG. Therefore, the waveform is slightly different). On the other hand, the vibration spectrum when the tip of the tip is dipped in the sample or the like (water in this case) by 3 mm is shown in FIG. 8, and the vibration spectrum when the tip of the tip is dipped in the sample or the like by 10 mm is It is shown in FIG. Comparing FIG. 7, FIG. 8 and FIG. 9, the downward peak that appeared at 760 Hz as the tip 4 was immersed in the sample etc. was 720H.
It can be seen that the frequency shifts to the low frequency side such as z and 630 Hz. Therefore, a certain amount of vibration is applied from the vibration generating means 6, and the tip 4 is brought closer to the sample or the like while monitoring the vibration frequency and the vibration intensity when the tip 4 is mounted, and the tip 4 contacts the liquid surface. The liquid level of the sample or the like can be detected by the liquid level detection unit 16 based on the change in the vibration frequency and the vibration intensity at the instant. Immersion depth detector 1
4 detects how much the downward peak of 760 Hz in this air is shifted, thereby detecting the immersion depth of the chip 4 in the sample or the like.

A vibration frequency and a vibration intensity in a state in which a certain amount of vibration is applied from the vibration generating means 6 and the sample 4 is not inhaled, and the vibration frequency when the sample is injected. Also, the amount of inhaled sample or the like can be detected from the vibration intensity. The sample 4 or the like can be agitated by bringing the tip 4 or the pipette 2 itself inserted into the pipette 2 into contact with a container such as the sample or the sample or the like while applying a certain amount of vibration from the vibration generating means 6. ..

After inhaling or ejecting a sample or the like, the liquid droplets formed on the tip of the chip 4 are shaken off by applying a constant vibration intensity having a predetermined vibration frequency from the vibration generating means 6 to shake off the liquid droplets. It is possible to improve the accuracy of injection, and it is also possible to prevent the droplets of the sample or the like from being scattered during the movement of the pipette 2 while the sample 4 is being sucked into the tip 4. By attaching and detaching the tip 4 while vibrating the pipette 2 to reduce the friction coefficient generated between the pipette 2 and the tip 4,
It is possible to strengthen the fitting of the chip 4 with respect to.

[0013]

EXAMPLE FIG. 10 shows an example. An impulsor 30 for generating vibration is attached to a portion of the pipette 2 near the side where the chip 4 is mounted, and a pickup 32 for detecting the vibration is attached to the pipette 2 at a portion near the chip 4. The impulsor 30 and the pickup 32 can be realized by a piezoelectric element, for example. An amplifier 34 is provided to amplify the detection signal of the pickup 32.
Is provided to monitor the vibration frequency for detecting the presence / absence of the tip 4, the vibration frequency for detecting that the fitting state of the tip is bad, the vibration frequency for detecting the liquid surface, and the immersion depth of the tip. Bandpass filters 36a, 36b respectively set to the vibration frequency for
36c, ... Are provided, and each bandpass filter 36 is provided.
a-36b, 36c, ... AC-DC converters 38a, 38b, 3 such as rectifiers for converting AC signals into DC signals
8c, ... Are connected. AC-DC converter 38
An AD converter 40 is provided to convert the DC signals from a, 38b, 38c, ... The computer implements chip presence / absence detection, fitting state detection, liquid level detection, and other functions from the signals at the respective frequencies. Impulcer 3
The 0 and the pickup 32 may be realized by a single element. The present invention is not limited to those configured to achieve all of the functions described in the embodiments, as long as it is configured to perform at least liquid level detection and to implement some other functions. Good.

[0014]

According to the present invention, the simple components of the vibration generating means and the vibration detecting means attached to the pipette provide the detection signal necessary for the automatic dispensing work, and the liquid level detection based on the signal is obtained. It can perform several other functions. Therefore, it is possible to realize an automatic dispensing device having a simple structure.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing the present invention.

FIG. 2 is a schematic front view for explaining the operation of the present invention.

FIG. 3 is a waveform diagram showing vibration by an impulse hammer.

FIG. 4 is a waveform diagram showing a detection signal by a pickup when a tip is not attached to a pipette.

FIG. 5 is a waveform diagram showing a detection signal by the pickup when the tip is correctly attached to the pipette.

FIG. 6 is a waveform diagram showing a detection signal by the pickup when the tip is not properly attached to the pipette.

FIG. 7 is a waveform diagram showing a detection signal by the pickup when the tip mounted on the pipette is held in the air. Figure 5 is an impulse hammer

Figure 8: Tip attached to pipette is 3mm from the tip
It is a wave form diagram which shows the detection signal by the pick-up when it is immersed in water up to.

[Figure 9] Tip attached to the pipette is 10m from the tip
It is a wave form diagram which shows the detection signal by the pick-up when it is immersed in water to m.

FIG. 10 is a schematic configuration diagram showing an embodiment.

[Explanation of symbols]

 2 Pipette 4 Tip 6 Vibration generation means 8 Detection means 10 Judgment means 12 Tip presence / absence detection section 14 Tip fitting state detection section 16 Liquid level detection section 18 Immersion depth detection section

Claims (2)

[Claims] 1. An automatic dispenser in which a disposable tip is attached to the tip of a pipette for sucking and discharging a sample or the like, the tip is immersed in the sample or the like to suck the sample or the like, and the sample is moved to a reaction container to discharge the sample or the like. In the injecting device, a vibration generating means provided in the pipette for vibrating the pipette, a vibration detecting means provided in the pipette for detecting the vibration of the pipette, the chip of the sample from the frequency of the detected vibration and its vibration intensity. An automatic dispensing device comprising: a determination unit that detects at least a contact with a liquid surface such as. 2. The automatic dispensing device according to claim 1, wherein the vibration generating means also serves as the vibration detecting means.