JPH0110606Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a liquid sample pipettor, in particular,
Suitable for use when performing multiple analysis on one sample using a biochemical analyzer, etc., to aspirate the amount of sample required for the multiple analysis and sequentially dispense it into multiple reaction tubes. This invention relates to a liquid sample pipettor.

In conventional liquid sample pipettes of this type, a single syringe usually aspirates and dispenses a sample into a sample dispensing tube. Therefore, in order to increase the accuracy of dispensing during dispensing, if the plunger of the syringe is made thinner and the stroke is lengthened, the stroke for suction is twice as many as the number of analysis items, making it extremely long. For example, if the ejection stroke per item is set to at least 1 mm to ensure accuracy, if the number of analysis items is 20, the suction stroke will be at least 20 mm. Therefore, the cycle time required for analysis becomes longer, leading to a reduction in processing capacity. Conversely, if the suction stroke is shortened in order to shorten the cycle time, the single discharge stroke will also be shortened. For example, if the upper limit of the suction stroke derived from the cycle time is 8 mm, and the number of analysis items is 20, the discharge stroke per item is
It will be 0.4mm or less. When the discharge stroke becomes short in this way, it becomes difficult to obtain desired dispensing accuracy. In the end, the conventional liquid sample pipettor of this type has the drawback of not being able to achieve both sample dispensing accuracy and throughput.

This idea was made with this in mind,
A large-diameter sample suction syringe and a small-diameter sample discharge syringe are separately provided, and the large-diameter sample suction syringe is used to aspirate a large amount of sample into the sample dispensing tube at high speed. Note: Discharge the sample from the tube with high accuracy in small amounts using a small-diameter sample discharging syringe, and at the same time as pulling down the plunger of the sample discharging syringe, simultaneously dispense the sample with the sample suction syringe. The present invention provides a liquid sample pipettor which eliminates the above-mentioned drawbacks by cleaning the inside of the tube, thereby achieving both improved sample dispensing accuracy and improved throughput.

This invention will be explained in detail below based on the embodiment shown in the drawings. Note that this invention is not limited to this.

1 shown in FIG. 1 is an embodiment of the liquid sample pipettor of this invention.

This liquid sample pipettor 1 consists of a large-diameter sample suction syringe 2, a switching pot 6 connected to the liquid port 3 of the sample suction syringe 2, and one position of the switching pot 6 (flow path indicated by a broken line). a cleaning liquid suction tube 7 that communicates with the sample suction syringe 2 at a position), and a sample dispensing tube that communicates with the sample suction syringe 2 at another position of the switching pot 6 (flow path position indicated by a solid line). 8 and
It consists of a small-diameter sample discharging syringe 9 having a liquid port 10 connected to a portion of the sample dispensing tube 8 near the switching pot 6.

The diameter of the piston 4 of the sample suction syringe 2 is approximately 8
Syringe control mechanism 1 that moves a nut b by rotation of a screw shaft a connected to a pulse motor (not shown) to perform suction and discharge into a syringe.
A piston rod 5 is connected to 2. This syringe control mechanism 12 is controlled by a control circuit 14 and can move the piston 4 at a speed of 4 mm/sec.

The plunger 11 of the sample discharge syringe 9 is connected to a syringe control mechanism 13 that is exactly the same as the syringe control mechanism 12, and the plunger diameter is approximately
It is 3.6mm. The syringe control mechanism 13 is also controlled by the control circuit 14, and the plunger 11 is
It can be moved at a speed of mm/sec.

The capacity from the nozzle portion 15 of the sample dispensing tube 8 to the connection portion 16 of the liquid port 10 of the sample discharge syringe 9 is 500μ. This capacity was determined to be larger than 400μ, which is equivalent to 20 items, assuming that the average sample amount required for analysis of one item is 20μ.

17 is a cleaning liquid tank containing pure water W. 18
is a sample cup, which contains a liquid sample S.
19 is a nozzle cleaning tank in which the cleaning liquid D after cleaning the inside of the sample dispensing tube 8 is discarded. Note that this nozzle cleaning tank 19 is supplied with pure water from below and overflows from the side, and when the nozzle part 15 is immersed in this nozzle cleaning tank 19, the outside of the nozzle part 15 is cleaned with pure water. Ru.

20 is a nozzle moving mechanism that moves the nozzle section 15 of the sample dispensing tube 8. Also, 21...
...40 is a reaction tube provided corresponding to each analysis item.

The operation of this liquid sample pipettor 1 will be explained below. First, in order to set the initial state, the nozzle part 15 is placed in the nozzle cleaning tank 19, the switching knob 6 is set to the solid line position, and the piston 4 is pulled to open the sample suction syringe 2. The sample dispensing tube 8 is filled with pure water, and the plunger 11 is pulled to fill the sample discharging syringe 9 with pure water, and then the piston 4 is pushed back to the intermediate position. This is the initial state, which corresponds to the beginning of one dispensing cycle time, and is the state at time t ₀ in FIG. 2.

Next, an example of the dispensing operation will be described with reference to FIG. 2. (i) From time _t0 to _t1 , the nozzle section 15 is moved to the sample cup 18. This time is, for example, 0.5 seconds.

(ii) From time t ₁ to t ₂ as well, the piston 4 is pulled to suck the liquid sample S into the sample dispensing tube 8 . Since the amount of suction was 400μ, the time required for this suction was 2 seconds. FIG. 1 shows the state at this time.

(iii) From time t ₂ to t ₃ , the nozzle part 15
is moved to the reaction tube 21. This time is, for example, 0.5 seconds.

(iv) From time t ₃ to t ₄ , the plunger 11 is
Push up the sample S by 20 μm and dispense it into the first reaction tube 21 by 20 μm required for analysis of one item.
This time is 0.5 seconds.

(v) From time t ₄ to t ₄₂ , the same operations as in (iii) and (iv) above are repeated, and the second reaction tube 22 is
Samples are dispensed into up to 20 reaction tubes 40, respectively.
The time required for this is 19 seconds.

(vi) From time _t42 to time _t43 , the nozzle section 15 is moved to the nozzle cleaning tank 19. This time is, for example, 0.5 seconds.

(vii) From time t ₄₃ to t ₄₄ , the piston 4 is pushed up and 800μ of pure water is sent into the sample dispensing tube 8, and at the same time the plunger 11 is pulled and pure water is sucked into the sample discharge syringe 9. do. Since this time is 4 seconds, the pure water sucked into the sample discharging syringe 9 is about 163μ, and about 637μ of the pumped pure water cleans the sample dispensing tube 8 and the nozzle cleaning tank 19.
is discharged to. At this time, the nozzle section 15 is immersed in the nozzle cleaning tank 19.

(viii) From time _t44 to _t45 , the switching valve 6 is switched to the dotted line position. For example, this time
It is 0.5 seconds. At this time, the plunger 11 is continuously pulled.

(ix) From time t ₄₅ to t ₄₆ , the piston 4 is pulled, and pure water W is sucked into the sample suction syringe 2 from the cleaning liquid tank 17 via the cleaning liquid suction tube 7 . The inhalation volume is 700μ, and the duration is 3.5 seconds. At this time, plunger 11
is being drawn continuously, and approximately 325 μm of pure water is sucked into the sample discharge syringe 9 at time _t46 .

(x) From time t ₄₆ to t ₄₇ , the switching knob 6 is switched to the solid line position. Further, the plunger 11, which has been continuously pulled since time _t43 , stops at a position where it has been pulled down by about 40 mm. The sample injection syringe 9 is filled with 400μ pure water.
The time during this period is 2 seconds.

Approximately 237 μ of pure water sucked into the sample dispensing syringe 9 after time t ₄₄ was sucked from inside the sample dispensing tube 8, and this amount is on the nozzle portion 15 side of the sample dispensing tube 8. Pure water is sucked in from the nozzle cleaning tank 19.

() From time t ₄₇ to t ₄₈ , piston 4
is pushed back to the intermediate position, which causes 300μ
of pure water W is discharged into the nozzle cleaning tank 19 through the sample dispensing tube 8. As a result, the inside of the nozzle portion 15 is further cleaned.
The time required for this is 1.5 seconds. The state at time _t48 has returned to the initial state.

Through steps (i) to () above, one cycle of dispensing one sample S is completed. The cycle time is
It is 34.5 seconds. Therefore, this liquid sample pipettor 1
If 20 items are analyzed for one sample using the , and an average of 20μ of sample is dispensed per item, approximately 100 samples can be processed per hour.

In addition, in order to maintain the same dispensing accuracy, only one syringe, which is the same as the sample dispensing syringe 9, was used.
If a conventional liquid sample pipettor of this kind were constructed, it would take about 10 seconds to aspirate the sample, about 20 seconds to dispense, and about 20 seconds to wash, so the cycle time would be at least about 50 seconds, This means that only about 70 samples can be processed per hour.

As described above, according to the liquid sample pipettor of this invention, it is possible to improve both the pipetting precision and the throughput.

Further, since the sample dispensing tube can be cleaned by flowing a large amount of cleaning liquid using a large-capacity sample suction syringe, an excellent cleaning effect can be obtained.

As shown in FIGS. 3A and 3B, other embodiments include one that includes a plurality of sample dispensing tubes 8a and a sample dispensing syringe 9a, and one that includes a plurality of switching tips 6b and a sample dispensing tube 8b. Examples include those equipped with a sample discharge syringe 9b. In these cases, the sample suction syringes 2a, 2b need to have a significantly larger diameter than the plurality of sample discharge syringes 8a, 8b.

[Brief explanation of drawings]

Fig. 1 is a configuration explanatory diagram of an embodiment of the liquid sample pipettor of this invention, Fig. 2 is a time chart of an example of the operation of the liquid sample pipettor of Fig. 1, and Figs. FIG. 7 is a schematic structural explanatory diagram of another example of the sample pipettor. 1, 1a, 1b...liquid sample pipettor, 2,
2a, 2b...Syringe for sample inhalation, 3...Liquid port, 6, 6a, 6b...Switching pot, 7, 7a,
7b...Washing liquid suction tube, 8, 8a, 8b...
...Sample dispensing tube, 9, 9a, 9b...Syringe for sample discharge, 10...Liquid port.

Claims (1)

[Scope of utility model registration request] a large-diameter sample suction syringe, at least one switching pot connected to the liquid port of the sample suction syringe, a cleaning liquid suction tube communicating with the sample suction syringe at one position of the switching pot, and the switching pot at least one syringe connected to the sample aspiration syringe at another position of the sample aspiration syringe.
A liquid sample pipettor consisting of two sample dispensing tubes and a small diameter sample discharging syringe having a liquid port connected to a portion of the sample dispensing tube near the switching tip.