JPH1090281A - Pipetting method, pippeting device, and memory medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pipetting method which can decide the viscosity of a carried liquid before it is sucked, without reducing its processing capacity; a pipetting device applying this pipetting method; and a memory medium storing a program in order to operate the pipetting device. SOLUTION: By using a pipetting device which has a pump to suck and discharge a carried liquid from the opening of a nozzle by communicating to the nozzle, and a pressure detecting means to detect the pressure of an air flow passage between the pump and the opening of the nozzle, the pressure variation of the air flow passage between the pump and the opening of the nozzle is detected (S9) depending on the output signal from the pressure detecting means, in the air exhausting time (S8) in an attached sample removing process, and the viscosity of the carried liquid is decided depending on the pressure variation (S10 and S17).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pipetting method for detecting a viscosity of a liquid to be conveyed in a pipetting operation for sucking a liquid to be conveyed in a container and discharging the liquid at a desired position, and a pipetting method therefor. And a storage medium storing a program for controlling the pipetting apparatus.

[0002]

2. Description of the Related Art For example, when a liquid sample such as serum, blood, urine or the like of a human or an animal, or a liquid to be conveyed such as a medicine, a washing liquid, an adhesive, etc. is sucked out of a container and discharged at a predetermined position, If the type is not determined, 1
The viscosity may vary greatly between conveyances. When sucking and discharging particularly high-viscosity liquid to be conveyed, avoid abrupt operation and perform suction and discharge slowly, or complete the liquid to be conveyed after a predetermined time after suction and discharge. If a predetermined amount of liquid to be conveyed cannot be sucked or discharged unless the suction or discharge is performed. In other words, the transported liquid having a very high viscosity, such as the serum of some animals, has a large flow resistance,
It is necessary to take some time for suction and discharge.

In the conventional pipetting apparatus, when actually sucking the liquid to be conveyed, the pressure change in the nozzle pipe is monitored to detect a clogging state in the nozzle, and the suctioned liquid to be conveyed becomes high. It was determined whether it was a viscosity.

However, in the above-described conventional pipetting apparatus, the viscosity is detected when the liquid to be conveyed is actually suctioned. Therefore, it is determined that the viscosity of the liquid to be conveyed is high during or after suction. There is a problem that it is not possible to perform appropriate suction according to the viscosity, and the amount of suction becomes inaccurate. Therefore, for example, when such a pipetting device is employed in various clinical test devices, it may not be possible to suction and discharge an appropriate amount of the liquid to be conveyed,
As a result, the reliability of the inspection result is impaired.

In order to solve such a problem, when it is found that the viscosity of the liquid to be conveyed is high, it is also conceivable to once discharge the liquid to be conveyed which has already been sucked and to execute the suction operation again in accordance with the viscosity. However, this requires a long processing time, and the processing performance is significantly reduced. And one
In a pipetting apparatus that is programmed to change the nozzle tip after each suction, the nozzle tip is changed before re-suction, so that the consumption of the nozzle tip increases, thereby increasing the cost. I will.

Further, it is conceivable that all the liquid to be conveyed is sucked and discharged slowly in accordance with the liquid to be conveyed having a high viscosity, but this further reduces the processing capacity.

[0007]

DISCLOSURE OF THE INVENTION The present invention has been conceived in view of the above circumstances, and has a pipetting method capable of judging the viscosity of a liquid to be conveyed before sucking it without reducing the processing capacity, and It is an object of the present invention to provide a pipetting apparatus employing the pipetting method and a storage medium storing a program for operating the pipetting apparatus.

In order to solve the above problems, the present invention takes the following technical measures.

According to the first aspect of the present invention, a pump communicating with a nozzle and sucking and discharging a liquid to be conveyed from an opening of the nozzle, and detecting a pressure of an air flow path between the pump and the opening of the nozzle. The distance between the nozzle opening and the liquid surface of the liquid to be conveyed is reduced while suctioning or discharging air from the nozzle opening using a pipetting apparatus having Liquid level detection for detecting the liquid level of the liquid to be conveyed by detecting a pressure change in the air flow path between the pump and the nozzle opening due to contact with the liquid level based on an output signal from the pressure detection means. And a suction step of sucking a predetermined amount of liquid to be conveyed from the opening of the nozzle, and after the liquid level detection step and before the suction step, the opening of the nozzle is separated from the liquid level of the liquid to be conveyed, Sky from opening And an attached sample removing step of blowing off the liquid to be conveyed attached near the opening of the nozzle by ejecting the liquid. In the attached sample removing step, the pipetting method is performed between the pump and the opening of the nozzle. A pipetting method is provided, wherein a change in pressure in an air flow path is detected based on an output signal from a pressure detecting means, and the viscosity of the liquid to be conveyed is determined based on the change in pressure.

According to this pipetting method, in the attached sample removing step, a pressure change in the air flow path between the pump and the nozzle opening is detected based on an output signal from the pressure detecting means, and the pressure change is detected. Since the viscosity of the liquid to be conveyed is determined based on this, it is possible to determine the viscosity of the liquid to be conveyed before actually sucking the liquid to be conveyed in the suction step. Moreover,
Since this determination is performed simultaneously with the attached sample removing step, the processing time is not extended.

Therefore, at the time of sucking and discharging the liquid to be conveyed, it is possible to perform an appropriate suction and discharge operation in accordance with the viscosity of the liquid to be conveyed, so that a predetermined amount of the liquid to be conveyed can be accurately sucked and discharged. Furthermore, the processing time does not become unnecessarily long, and a reduction in processing capacity can be prevented. Further, in the case where the nozzle tip is replaced each time the liquid to be conveyed is sucked once, the nozzle tip is not wastefully consumed, which is economical.

According to the second aspect of the present invention, a pump communicating with the nozzle and sucking and discharging the liquid to be conveyed from the opening of the nozzle, and the nozzle and the container containing the liquid to be conveyed are relatively moved. Drive device, pressure detection means for detecting the pressure of the air flow path between the pump and the opening of the nozzle,
A control device that receives the output signal from the pressure detection unit and controls the pump and the driving device, and controls the pump and the driving device by the control device, thereby sucking or discharging air from the nozzle opening to discharge the nozzle. The distance between the nozzle opening and the liquid surface of the liquid to be conveyed is reduced, and the pressure change in the air flow path between the pump and the nozzle opening due to the nozzle opening coming into contact with the liquid surface of the liquid to be conveyed is detected. The liquid level of the liquid to be conveyed is detected by detecting based on the output signal from the means, and thereafter, the nozzle opening is separated from the liquid level of the liquid to be conveyed, and the nozzle is discharged by discharging air from the nozzle opening. The pipetting device blows off the liquid to be transported attached near the opening of the nozzle, and the control device discharges air from the opening of the nozzle to attach the liquid near the opening of the nozzle. When the transported liquid is blown off, the pressure change in the air flow path between the pump and the nozzle opening is detected based on an output signal from the pressure detecting means, and the viscosity of the transported liquid is determined based on the pressure change. A pipetting device is provided, wherein

According to this pipetting apparatus, since the pipetting method of the present invention is employed, the effects of the method can be enjoyed.

The nozzle and the pump may be connected to each other directly or via a connector, and may be arranged close to each other. Alternatively, the nozzle and the pump may be connected to each other via a flexible tube so as to be relatively movable. . The nozzle may be configured integrally as a whole, or may be configured by connecting a plurality of components. The opening of the nozzle is generally formed at the tip of the nozzle, but may be formed at another position. The pump may be, for example, a syringe pump including a cylinder and a pulse motor that reciprocates a plunger of the cylinder, or may be another type of pump.

The liquid to be conveyed may be, for example, a liquid sample such as serum, blood, urine, etc., but is not limited thereto, and may be a reagent, a cleaning agent, an adhesive, or the like.
Any type of liquid may be used.

The driving device for relatively moving the nozzle and the container containing the liquid to be conveyed may be composed of, for example, a rack and pinion mechanism and an electric motor, or may be another mechanism. When the nozzle is moved, only the nozzle may be moved, or the nozzle and the pump may be moved integrally.

The pressure detecting means for detecting the pressure in the air flow path between the pump and the opening of the nozzle may be directly installed in the air flow path, or may connect the pump, the nozzle, or the pump and the nozzle. It may be configured to communicate with the air flow path via a connector or a conduit extending from the flexible tube. Further, the pressure detecting means may be a combination of a diaphragm and a semiconductor strain detecting element, for example, or may have another configuration.

The control device can be realized by, for example, a microcomputer or a personal computer.

According to a preferred embodiment, the control device is configured to control the air flow between the pump and the nozzle opening when blowing the liquid to be conveyed attached near the nozzle opening by discharging air from the nozzle opening. When the pressure change in the passage is equal to or more than a predetermined value, the pump determines that the viscosity of the liquid to be conveyed is equal to or more than a predetermined value, and sucks and discharges the liquid to be conveyed from the nozzle opening. To perform suction and discharge more slowly than usual.

In this manner, a predetermined amount of the liquid to be transported can be accurately suctioned and discharged even if the liquid to be transported has a high viscosity. Further, in the case of the transported liquid having a low viscosity, the suction and discharge are not performed slowly, so that the processing capacity does not decrease.

Slowly performing suction and discharge includes, for example, when a syringe pump is used, when the moving speed of the plunger is reduced, and when the air flow between the pump and the nozzle opening after the plunger is moved. This includes all cases where the system waits until the pressure of the road reaches a predetermined value and a case where both are combined.

According to another preferred embodiment, the nozzle comprises a nozzle body and a nozzle tip which is detachably attached to the nozzle body and has an opening.

With this configuration, it is possible to store the sucked liquid to be conveyed only inside the nozzle chip, and by exchanging the nozzle chip for each suction and discharge of the liquid to be conveyed. In addition, mixing of other liquid to be conveyed can be favorably prevented. Therefore, when the pipetting device is employed in, for example, a clinical test device, the test can be performed accurately and hygienically.

According to the third aspect of the present invention, a pump communicating with the nozzle and sucking and discharging the liquid to be conveyed from the opening of the nozzle, and detecting the pressure of the air flow path between the pump and the opening of the nozzle. A storage medium storing a program for operating a pipetting apparatus having a pressure detecting means for reducing the distance between the nozzle opening and the liquid surface of the liquid to be conveyed while sucking or discharging air from the nozzle opening. Detecting the pressure change of the air flow path between the pump and the nozzle opening due to the nozzle opening coming into contact with the liquid surface of the liquid to be conveyed based on the output signal from the pressure detecting means. A liquid level detecting program for executing a liquid level detecting step of detecting a liquid level of the liquid; a suction program for executing a suction step of sucking a predetermined amount of liquid to be conveyed from an opening of a nozzle; In front of the out after the step and the suction process,
An attached sample removing program for executing an attached sample removing step in which the opening of the nozzle is separated from the liquid surface of the liquid to be conveyed and air is ejected from the opening of the nozzle to blow off the liquid to be attached attached near the nozzle opening; In the sample removal step, a pressure change in the air flow path between the pump and the opening of the nozzle is detected based on an output signal from the pressure detection means, and the viscosity of the liquid to be conveyed is determined based on the pressure change. And a storage medium storing a program including the program.

According to this storage medium, the pipetting method of the present invention can be implemented by operating the CPU or the like of the pipetting apparatus based on the stored program.

The storage medium may be, for example, a ROM, but is not limited thereto, and may be a flexible disk, a CD-ROM, an EEPROM, or the like.

[0027] Other features and advantages of the present invention will become more apparent from the detailed description given below with reference to the accompanying drawings.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be specifically described below with reference to the drawings.

FIG. 1 is an external perspective view showing an example of a sample inspection device provided with a pipetting device according to the present invention. In this sample inspection device 1, a pipetting device 3 described later is provided in a housing 2. The housing 2 is provided with an opening 5 that can be opened and closed by a lid 4 on the front surface of the housing 2. The lid 4 is provided with a touch panel type display device 6 also serving as an operation switch on a front portion in an open state, and has a function as an operation panel of the sample inspection device 1. Further, the housing 2 has a slide table 7 slidable in the direction of arrow a so as to move from a position in front of the opening 5 of the housing 2 to a depth inside the housing 2.
Is provided. On an upper surface of the slide table 7, a holder 9 for standing and holding a plurality of containers 8 accommodating a liquid sample as an example of a transported liquid to be inspected, and a plurality of reagent pads 1 for inspecting the liquid sample.
0, and a measuring device (not shown) for measuring a change in coloration after the liquid sample is spotted on the reagent pad 10. In addition, a printer 11 that prints out test results and the like is installed on the lid 4 adjacent to the display device 6.

In the sample inspection apparatus 1, for example, serum is used as a liquid sample, and when this serum is spotted on the reagent pad 10 by the operation of the pipetting device 3, an optical fiber is thereafter attached to the reagent pad 10. After irradiating monochromatic light through the light source, the reflected light is read by a photodiode. Then, the measurement data is analyzed using a well-known method, and various components in the serum are displayed on the display screen of the display device 6 or printed out on a recording paper using the printer 11.

FIG. 2 is a schematic overall configuration diagram of the pipetting apparatus 3, and the nozzle 21 is constituted by a nozzle body 22 and a nozzle tip 23. That is, the nozzle tip 23 is made of resin, is attached to a small-diameter portion of the tip of the nozzle body 22 so as to be freely inserted and withdrawn, and has an opening at the tip.
A syringe pump 25 is connected via a joint pipe 24 to an end of the nozzle body 22 opposite to the nozzle tip 23 side. The syringe pump 25 includes a cylinder 26 and a plunger 27 that moves in the cylinder 26.
And a pulse motor 28 for reciprocating the plunger 27. The pulse motor 28
The mechanism for converting the rotational movement of the output shaft into the linear movement of the plunger 27 is well known and will not be described. The nozzle 21 and the syringe pump 25 are mounted on a movable table (not shown) driven by a motor / motor 29 via a rack and pinion mechanism or a belt / pulley mechanism, and are orthogonal to the vertical direction and the direction of arrow a in FIG. It is configured to be movable in the horizontal direction. A branch pipe 30 branches from a joint pipe 24 connecting the nozzle 21 and the syringe pump 25, and a pressure sensor 31 is connected to the branch pipe 30.

The control device 32 controls the movement of the nozzle 21 and the syringe pump 25, that is, the driving of the electric motor 29, and the driving of the syringe pump 25, that is, the driving of the pulse motor 28. The control device 32 has a CPU
33, a ROM 34, a RAM 35, and an input / output interface 36.
6 includes a pulse motor 28, an electric motor 29, a pressure sensor 3
1, an operation unit 37, a display unit 38, and a printing unit 39 are connected. The operation unit 37 and the display unit 38 are configured by the display device 6 of FIG.
Is constituted by the printer 11 of FIG.

That is, the pulse motor 28 is controlled by the control device 32 to move the plunger 27 of the syringe pump 25 so that the nozzle 21 sucks and discharges the liquid sample in the container 8 or sucks air. And discharge. The electric motor 29 is controlled by the control device 32 to move the nozzle 21 and the syringe pump 25 up and down and to move horizontally so that the opening at the tip of the nozzle tip 23 can be immersed in the liquid sample in the container 8, as shown in FIG.
Or contact with the reagent pad 10. Pressure sensor 31
Is composed of, for example, a diaphragm and a semiconductor strain detecting element, detects the pressure in the air flow path between the syringe pump 25 and the opening of the nozzle 21, and outputs an analog signal of a voltage corresponding to the pressure. The control device 32 controls the entire sample inspection device 1. The CPU 33 operates based on a program stored in the ROM 34 in advance, and
The control data is output to the pulse motor 28, the electric motor 29, the display unit 38, the printing unit 39, and the like based on signals from the control unit 1 and the operation unit 37. The ROM 34 stores programs, predetermined data, and the like. The RAM 35 is backed up with a power supply by a battery (not shown) and stores various data. The input / output interface 36
Analog / digital conversion, serial / parallel conversion,
Alternatively, it controls transmission and reception of signals between the CPU 33 and an external device, such as timing control. The operation unit 37 supplies a command signal to the control device 32 according to a user's touch operation on the display screen of the display device 6 (FIG. 1). The display unit 38 is controlled by the control device 32 and displays various characters or figures on the display screen of the display device 6 (FIG. 1). The printing unit 39 is controlled by the control device 32 and prints out the analysis result and the like on recording paper. This printing unit 39 is actually the printer 11 of FIG.

That is, the syringe pump 25 constitutes a pump that communicates with the nozzle 21 and sucks and discharges the liquid sample from the opening of the nozzle 21. The electric motor 29 is
It constitutes a part of a driving device for moving the nozzle 21. The pressure sensor 31 includes the syringe pump 25 and the nozzle 2
Pressure detecting means for detecting the pressure of the air flow path between the first opening and the first opening is formed. The control device 32 constitutes a control device that receives an output signal from the pressure sensor 31 and controls the pulse motor 28 and the electric motor 29. ROM34
Reduces the distance between the opening of the nozzle 21 and the liquid surface of the liquid sample while sucking or discharging air from the opening of the nozzle 21, and the syringe pump 25 A liquid level detection program for executing a liquid level detection step of detecting a liquid level of a liquid sample by detecting a pressure change of an air flow path between the pressure sensor and the opening of the nozzle 21 based on an output signal from the pressure sensor 31. ,
A suction program for executing a suction step of sucking a predetermined amount of the liquid sample from the opening of the nozzle 21; and, after the liquid level detection step and before the suction step, separating the opening of the nozzle 21 from the liquid level of the liquid sample; An attached sample removing program for executing an attached sample removing step of blowing out a liquid sample attached to the vicinity of the opening of the nozzle 21 by discharging air from the opening of the nozzle 21, and an opening of the syringe pump 25 and the opening of the nozzle 21 in the attached sample removing step. And a viscosity determination program for detecting a pressure change in the air flow path between the air sample and the liquid sample based on an output signal from the pressure sensor 31 and determining a viscosity of the liquid sample based on the pressure change. Make up the medium.

In the sample inspection apparatus 1, a predetermined amount of the liquid sample in the container 8 is sucked by the nozzle 21, the liquid sample is spotted on the reagent pad 10, and the color sample of the reagent pad 10 is changed to change the liquid sample. Is performed, and all of them are controlled and automatically performed by the control device 32. The procedure of the suction process including the step of determining the viscosity of the liquid sample among the control operations by the control device 32 will be described with reference to the flowchart shown in FIG.

Now, it is assumed that the tip opening of the nozzle tip 23 exists at a position at a predetermined height right above the container 8 containing the liquid sample. First, the CPU 33 controls the pulse motor 28 to move the plunger 27 of the syringe pump 25 to the discharge side, and discharge air from the tip opening of the nozzle tip 23 (S1). Further, the CPU 33 controls the electric motor 29 so that the nozzle 21 and the syringe pump 25
Is lowered (S2). Then, the CPU 33 monitors the output signal from the pressure sensor 31 and determines whether the pressure detected by the pressure sensor 31 has increased to a predetermined value (S
3). That is, the tip opening of the nozzle tip 23 is
When the liquid reaches the liquid surface of the liquid sample inside, the discharge of air is hindered by the liquid sample, and the pressure detected by the pressure sensor 31 sharply increases. Thus, the liquid surface of the liquid sample is to be detected.

If the pressure detected by the pressure sensor 31 rises to a predetermined value (S3: YES), it means that the tip opening of the nozzle tip 23 has reached the liquid surface of the liquid sample in the container 8, and the CPU 33 That is, the height is RA
It is stored in M35 (S4). This position can be easily obtained by, for example, providing a rotary encoder rotated by the electric motor 29, counting the number of pulses from the rotary encoder, and calculating the descending distance of the nozzle 21 from a predetermined position. Further, the CPU 33
The motor 29 is controlled to stop the lowering of the nozzle 21 and the syringe pump 25 (S5), and the pulse motor 28 is controlled to stop the movement of the plunger 27, thereby stopping the discharge of air from the tip opening of the nozzle tip 23. (S6). The order of operations in S4 to S6 is arbitrary. Then, the CPU 33 controls the electric motor 29 to raise the nozzle 21 and the syringe pump 25 by a predetermined distance (S7). Of course, the nozzle 21 and the syringe pump 25 may be raised to their original positions.

Further, the CPU 33 controls the pulse motor 28 so that the plunger 2 of the syringe pump 25
7 is moved to the discharge side to discharge air from the tip opening of the nozzle tip 23 (S8), and the liquid sample attached to the vicinity of the tip opening of the nozzle tip 23 when the liquid level is detected is blown off. Then, at this time, the CPU 33 monitors the output signal from the pressure sensor 31 to determine whether the pressure detected by the pressure sensor 31 has risen to a predetermined value or more and vibrates (S9). That is, when the viscosity of the liquid sample is not so high, the nozzle tip 23
Is not closed by the liquid sample, the pressure detected by the pressure sensor 31 does not suddenly increase when removing the liquid sample attached to the tip opening of the nozzle tip 23, and the liquid sample does not vibrate. When the viscosity of the liquid sample is very high, the tip opening of the nozzle tip 23 is closed by the liquid sample when detecting the liquid level. Therefore, when removing the liquid sample attached to the tip opening of the nozzle tip 23, the pressure sensor 31 is used. , And the detected pressure suddenly increases and vibrates. Therefore, it is trying to determine the viscosity of the liquid sample based on this pressure change.

If the pressure detected by the pressure sensor 31 rises above a predetermined value and vibrates (S9: YES), it means that the viscosity of the liquid sample is very high, so the CPU 33 sets the flag F to 1 (S10). ), The motor 29 is controlled to lower the nozzle 21 and the syringe pump 25 so that the tip opening of the nozzle tip 23 is immersed in the liquid sample in the container 8 (S11). The immersion depth is set to a depth at which a predetermined amount of the liquid sample can be reliably sucked. And CPU33
Determines whether the flag F is 1 (S12). If the flag F is 1 (S12: YES), the CPU 33 controls the pulse motor 28 because the liquid sample has high viscosity. Then, the plunger 27 is moved at a low speed to the suction side by a predetermined distance, and the liquid sample is sucked from the tip end opening of the nozzle tip 23 (S13). The reason why the liquid sample is sucked at a low speed is that it is difficult to reliably suck a predetermined amount of the liquid sample when sucked at a normal speed because the viscosity of the liquid sample is high. Further, the CPU 33 monitors the output signal from the pressure sensor 31 to determine whether the pressure detected by the pressure sensor 31 has increased to a predetermined pressure (S14). That is, the pressure detected by the pressure sensor 31 is a negative pressure during the suction, and the pressure detected by the pressure sensor 31 increases to the predetermined pressure by sucking the predetermined amount of the liquid sample. Wait until it is sucked in. If the pressure detected by the pressure sensor 31 increases to a predetermined pressure (S14: YE
S) Since the predetermined amount of the liquid sample has been sucked, the CPU 33 controls the electric motor 29 to
And the syringe pump 25 is raised to a predetermined position (S
15), this routine ends.

In S14, if the pressure detected by the pressure sensor 31 has not risen to the predetermined pressure (S14: N
O), returning to S14, and waiting for the pressure detected by the pressure sensor 31 to rise to a predetermined pressure. That is, the process waits until a predetermined amount of the liquid sample is sucked.

If the flag F is not 1 in S12 (S12: NO), the flag F is 0 and the viscosity of the liquid sample is not high, so the CPU 33 controls the pulse motor 28 to cause the plunger 27 to operate. The liquid sample is moved to the suction side by a predetermined distance at a normal speed, and the liquid sample is sucked from the tip end opening of the nozzle tip 23 (S16), and S14 is performed.
Proceed to. The reason why the liquid sample is sucked at the normal speed is that the liquid sample does not have a high viscosity, so that a predetermined amount of the liquid sample can be reliably sucked without sucking at a low speed.

In S9, if the pressure detected by the pressure sensor 31 does not increase to a predetermined value or more and does not vibrate (S9: NO), the viscosity of the liquid sample is not high.
U33 sets the flag F to 0 (S17), and S1
Proceed to 1.

In S3, if the pressure detected by the pressure sensor 31 has not risen to a predetermined value (S3: NO),
Since the tip opening of the nozzle tip 23 has not reached the liquid surface of the liquid sample in the container 8, the process returns to S <b> 3, where the tip opening of the nozzle tip 23 reaches the liquid surface of the liquid sample in the container 8. wait.

After the suction of the predetermined amount of the liquid sample is completed, the motor 33 is controlled by the CPU 33 to move the nozzle 21 and the syringe pump 25 in the horizontal direction orthogonal to the direction of the arrow a in FIG. The electric motor 29 is controlled to descend until the tip opening of the nozzle tip 23 contacts the reagent pad 10. In this state, the pulse motor 28 is controlled by the CPU 33, and the liquid sample is discharged from the opening at the tip of the nozzle chip 23, and is spotted on the reagent pad 10. This spotting is performed for each test piece when a plurality of test pieces are provided on the reagent pad 10. At this time, the CPU 33 checks the contents of the flag F, and discharges the liquid sample at a low speed if the viscosity of the liquid sample is high.
If the viscosity of the liquid sample is not high, the liquid sample is discharged at a normal speed.
The reagent pad 10 on which the liquid sample has been spotted changes its color in accordance with the content of the predetermined component contained in the liquid sample, and its reflectance is measured, and analysis is performed based on the reflectance.
Then, the analysis result is displayed on the display screen of the display device 6 and printed out by the printer 11. The mounting and dismounting of the nozzle tip 23 with respect to the nozzle body 22 is automatically performed by using the raising and lowering operations of the nozzle 21 and the syringe pump 25.

FIGS. 4 and 5 are explanatory diagrams of the output waveform of the pressure sensor 31 and the differential waveform thereof in the above-described series of operations. In FIG. 4, a solid line 41 represents an output waveform of the pressure sensor 31 for a liquid sample having a low viscosity, and a solid line 42 represents a differential waveform of an output of the pressure sensor 31 for a liquid sample having a low viscosity. In FIG. 5, a solid line 43 represents an output waveform of the pressure sensor 31 in the case of a high-viscosity liquid sample, and a solid line 44 represents a differential waveform of the output of the pressure sensor 31 in the case of a high-viscosity liquid sample.

In FIG. 5, focusing on the portions indicated by 43a and 44a, the detected pressure clearly rises and fluctuates. This is a pressure change generated when air is discharged from the tip opening of the nozzle tip 23 in order to remove the liquid sample attached near the tip opening of the nozzle tip 23 when the liquid surface of the liquid sample is detected. When the viscosity of the liquid sample is high, the opening of the tip of the nozzle tip 23 is closed by the liquid sample, and thus such pressure change is caused by the discharge of air. The corresponding part is shown in FIG.
However, since the viscosity of the liquid sample is not high, the opening at the tip of the nozzle tip 23 does not become closed and no pressure change occurs. Note that 41b,
42b, 43b, and 44b are pressure changes at the time of detecting the liquid level of the liquid sample, 41c, 42c, 43c, and 44c are pressure changes at the time of suction of the liquid sample, and 41d, 42d, 43d, and 44d are pressures at the time of spotting the liquid sample. Changes are shown respectively.

Note that, in the above embodiment, S in FIG.
In 9 it is determined that the viscosity of the liquid sample is high when the pressure detected by the pressure sensor 31 rises above a predetermined value and vibrates, but when the detection pressure rises above a predetermined value or when the detection pressure vibrates Alternatively, it may be determined that the viscosity of the liquid sample is high.

[Brief description of the drawings]

FIG. 1 is an external perspective view showing an example of a sample inspection device including a pipetting device according to the present invention.

FIG. 2 is a schematic overall configuration diagram of a pipetting device according to the present invention.

FIG. 3 is a flowchart illustrating a procedure of a suction process performed by the pipetting apparatus according to the present invention.

FIG. 4 is an explanatory diagram of an output waveform and a differential waveform thereof when the viscosity of the liquid sample is not high, by a pressure sensor provided in the pipetting apparatus according to the present invention.

FIG. 5 is an explanatory diagram of an output waveform and its differential waveform when the viscosity of a liquid sample is high, obtained by a pressure sensor provided in the pipetting apparatus according to the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 sample inspection device 3 pipetting device 6 display device 8 container 10 reagent pad 11 printer 21 nozzle 22 nozzle body 23 nozzle tip 25 syringe pump 28 pulse motor 29 motor 31 pressure sensor 32 control device

Claims (5)

[Claims] A pump that communicates with a nozzle and sucks and discharges a liquid to be conveyed from an opening of the nozzle; and a pressure detection unit that detects a pressure of an air flow path between the pump and the opening of the nozzle. Using a pipetting device having, while sucking or discharging air from the opening of the nozzle, the distance between the opening of the nozzle and the liquid surface of the transported liquid is reduced, and the opening of the nozzle is The liquid level of the liquid to be conveyed is detected by detecting a pressure change in an air flow path between the pump and the opening of the nozzle due to contact with the liquid level of the liquid based on an output signal from the pressure detecting means. A liquid level detection step, a suction step of sucking a predetermined amount of the liquid to be conveyed from the opening of the nozzle, and after the liquid level detection step and before the suction step, the opening of the nozzle is transported. A pipetting method for performing a process including a step of separating the liquid to be conveyed away from the liquid surface of the liquid to be sent and ejecting air from the opening of the nozzle to blow off the liquid to be conveyed attached near the opening of the nozzle. In the attached sample removing step, a pressure change in an air flow path between the pump and the opening of the nozzle is detected based on an output signal from the pressure detecting means, and the liquid to be conveyed is detected based on the pressure change. A pipetting method, comprising determining the viscosity of a pipette. 2. A pump communicating with a nozzle to suck and discharge a liquid to be conveyed from an opening of the nozzle, a driving device for relatively moving the nozzle and a container containing the liquid to be conveyed, and the pump And pressure control means for detecting the pressure of the air flow path between the opening of the nozzle, and a control device for receiving the output signal from the pressure detection means and controlling the pump and the driving device, By controlling the pump and the driving device by the control device, the distance between the opening of the nozzle and the liquid surface of the liquid to be conveyed is reduced while sucking or discharging air from the opening of the nozzle, A change in the pressure of the air flow path between the pump and the opening of the nozzle due to the opening of the nozzle contacting the liquid surface of the liquid to be conveyed is determined based on an output signal from the pressure detecting means. The liquid level of the liquid to be conveyed is detected by detecting the liquid level. Thereafter, the opening of the nozzle is separated from the liquid level of the liquid to be conveyed, and the air is discharged from the nozzle opening. A pipetting device that blows off the liquid to be conveyed attached to the vicinity, wherein the control device is configured to discharge the air to be conveyed from the vicinity of the opening of the nozzle by discharging air from the opening of the nozzle. A pressure change in an air flow path between the nozzle and the opening is detected based on an output signal from the pressure detection unit, and the viscosity of the liquid to be conveyed is determined based on the pressure change. Pipetting device. 3. The air flow path between the pump and the opening of the nozzle when discharging the air from the opening of the nozzle to blow off the liquid to be conveyed attached near the opening of the nozzle. When the pressure change is equal to or more than a predetermined value, it is determined that the viscosity of the liquid to be conveyed is equal to or more than a predetermined value, and when the liquid to be conveyed is sucked and discharged from the opening of the nozzle. 3. The pipetting apparatus according to claim 2, wherein the pump is controlled to perform suction and discharge more slowly than usual. 4. The pipetting apparatus according to claim 2, wherein the nozzle comprises a nozzle body and a nozzle tip detachably attached to the nozzle body and having the opening. 5. A pump communicating with a nozzle for sucking and discharging a liquid to be conveyed from an opening of the nozzle, and a pressure detecting means for detecting a pressure of an air flow path between the pump and the opening of the nozzle. A storage medium storing a program for operating a pipetting apparatus having, while sucking or discharging air from the opening of the nozzle, reducing the distance between the opening of the nozzle and the liquid surface of the transported liquid, By detecting a pressure change in an air flow path between the pump and the opening of the nozzle due to the opening of the nozzle being in contact with the liquid surface of the liquid to be conveyed, based on an output signal from the pressure detecting means, A liquid level detection program for executing a liquid level detection step for detecting the liquid level of the transported liquid; and a suction step of sucking a predetermined amount of the transported liquid from the opening of the nozzle. After the liquid level detecting step and before the sucking step, the opening of the nozzle is separated from the liquid level of the liquid to be conveyed, and the nozzle is discharged by discharging air from the opening of the nozzle. An attached sample removing program for executing an attached sample removing step of blowing off the liquid to be conveyed attached near the opening, and in the attached sample removing step, a pressure change in an air flow path between the pump and the opening of the nozzle is measured. A storage medium storing a program including a viscosity determination program for detecting a viscosity of the liquid to be conveyed based on a change in pressure detected based on an output signal from a pressure detection unit.