JP2904503B2 - Sampling method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for sampling a sample liquid or a reagent in an automatic chemical analyzer, an automatic immunological analyzer, or the like.

[Prior Art] In such an analyzer, it is necessary to accurately sample a predetermined amount of a sample solution. To perform this sampling accurately, a pipette mechanism is usually used. At this time, the tip is detachably fitted to the tip of the pipette in order to eliminate the need for cleaning the tip of the pipette.
A disposable tip system in which a tip is changed according to a liquid has been widely used recently.

[Problems to be Solved by the Invention] When a sample liquid or the like is suctioned and discharged by the pipette mechanism, a so-called wetting phenomenon occurs in which the sample liquid always remains on the inner and outer walls of the chip after the discharge. This wetting phenomenon differs every time depending on the material and surface condition of the chip, the type of the sample solution, the surface tension and the like. Therefore, even if the suction amount to the chip is accurately set by the suction pump, it is not possible to actually discharge all the amount sucked by the wetting phenomenon, and accurate weighing cannot be performed.

Therefore, the present invention has been made in view of such a point, and an object of the present invention is to provide a sampling method capable of discharging all of the liquid sucked by a pipette without leaving the liquid.

[Means for Solving the Problems] In order to achieve the above object, the sampling method of the present invention suctions a liquid into a disposable tip detachably fitted to a pipette tip and discharges the liquid to a container. In the sampling method, before sampling the liquid, the chip is inserted into the liquid and sucked, then the chip is taken out of the liquid and the whole sucked amount is discharged to wet the inside of the chip with the liquid to be sampled in advance. It is characterized by the following.

[Operation] As described above, if the inside of the chip is wetted with the sampling liquid in advance, an amount that is necessarily left by the wetting phenomenon can be left inside the chip in advance. Therefore, if a desired amount of the sampling liquid is suctioned next and the entire amount is discharged, the discharge amount becomes equal to the suction amount, and the sampling accuracy can be improved.

Hereinafter, an example of the sampling method of the present invention will be described in detail with reference to the drawings.

Embodiment FIG. 1 is an operation explanatory diagram when the present invention is applied to sampling of a sample liquid.

First, as shown in FIG. 1A, in a state where a tip (not shown or a pipette main body is provided above) 3 is inserted into a sample solution 2 accommodated in a sample cup 1 to a certain depth,
A desired amount is sucked by pulling out the piston 5 of the suction pump 4. The amount of insertion and suction of the tip is substantially equal to or greater than the amount of insertion and suction during actual sampling. Then, after removing the chip 3 from the sample liquid as shown in FIG. 3 (b) and stopping it, the piston in the suction pump is pushed in as shown in FIG. The liquid is discharged into the sample cup 1. As a result, a minimum amount of the sample liquid remains on the inner and outer walls of the chip, that is, the tip of the chip is wet with the sample liquid to be sampled.

Then, as shown by (d) in the figure, the chip 3 is lowered again, and a desired amount of the sample liquid in the sample cup 1 is sucked.
By moving the chip upward and rotating, the chip is transferred to the reaction vessel 6 as shown in FIG. In this state,
When the piston 5 is pushed in to discharge the sample liquid into the reaction vessel as shown in FIG. 3 (f), all the sample liquid sucked in FIG. A certain amount of the sample liquid remains.

With this configuration, the sample liquid is sucked and discharged by the chip pre-wetted with the sample liquid to be sampled.
The second suction of the sample liquid can be completely discharged.

On the other hand, when collecting the next different sample solution, the tip 3 is pulled out from the pipette body by a tip exchange mechanism (not shown), fitted and held near the sample cup 1 of the sample cup holding turntable, and Replace with another chip placed near the sample solution. Then, by repeating the above-described operation, a desired amount of the sample solution can be accurately collected with the chip wet with the sample solution to be constantly sampled.

The above description is an example of the present invention, and various modifications may be made in implementing the present invention. For example, in the above embodiment, the pre-suction performed before sampling is described as suctioning an amount equal to or larger than the actual sampling amount, but the present invention is not limited to this and may be smaller than the actual sampling amount. In the case where the suction amount is set to be small as described above, a slight error occurs in the sampling amount (discharge amount), but more accurate sampling can be performed as compared with the conventional method without the preliminary suction.

In the above embodiment, the case where the sample solution is sampled has been described.

As described above in detail, according to the present invention, the tip to be exchangeably mounted on the pipette tip is wetted with the liquid to be sampled before sampling the liquid, so that the weighing accuracy can be improved.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of the operation when the present invention is applied to sampling of a sample liquid. 1: sample cup 2: sample liquid, 3: tip 4: suction pump, 5: piston 6: reaction vessel

Claims (1)

(57) [Claims] In a sampling method wherein a liquid is sucked into a disposable tip detachably fitted to a pipette tip and discharged to a container, the tip is immersed in the liquid before sampling the liquid. A sampling method characterized in that after inserting and sucking, the chip is taken out of the liquid, and the whole sucked amount is discharged to wet the inside of the chip with the liquid to be sampled in advance.