JPH0445065B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a dispensing method, and particularly to a dispensing method for dispensing a predetermined amount of a sample such as serum or a reagent as a dispensing liquid.

[Prior Art] Generally, a dispensing nozzle is used when dispensing a liquid such as a specimen or a reagent into a test tube or the like. Due to the nature of such dispensing liquids, sufficient dispensing accuracy is often required, especially when the amount of dispensed liquid is a minute amount of 50μ or less. Injection causes errors.

An example of a conventional dispensing method as a measure against such errors will be explained with reference to FIGS. 1 to 3.

FIG. 1A shows an initial state, in which a diluent 12 is contained in the dispensing nozzle 10, and an air layer 14 is formed at the open end of the dispensing nozzle. This air layer 14 is for preventing contact between the diluent 12 and the next dispensed liquid to be aspirated.

Next, as shown in FIG. 1B, the sample 16, which is the dispensing liquid, is aspirated with the dispensing nozzle 10, and a predetermined amount of the sample 16 is sampled as shown in FIG. 1C. Dispensing nozzle 10 into empty test tube 1
8, aspirated sample 16 and diluent 12
into the test tube 18.

In the dispensing process as described above, when the sample 16 is aspirated and the dispensing nozzle 10 is pulled up, as shown in FIG.
6a may adhere, and the amount of adhesion becomes even larger, especially when sampling a highly viscous sample such as serum.

Therefore, the sample 16a attached to the dispensing nozzle 10
a suction port 20 connected to a vacuum pump close to the outer surface of the tip of the dispensing nozzle 10 to remove
When the dispensing nozzle 10 moves upward after sampling the sample 16, the dispensing nozzle 1
The sample 16a attached to the dispensing nozzle 10 is removed by sucking the sample 16a attached to the outer surface of the dispensing nozzle 10 into the suction port 20. In order to more effectively remove the sample 16a attached to the outer surface of the dispensing nozzle 10, it has been conventionally done to increase the vacuum pressure or to change the shape of the suction part 22 as shown in FIG. There is.

However, in the conventional dispensing method as described above, although the sample 16a adhering to the outer surface of the dispensing nozzle 10 can be easily removed, a small amount of the sample 16 inside the dispensing nozzle 10 is also removed from the nozzle. If the amount of sample to be sampled with the dispensing nozzle 10 is small (e.g.
10μ) had the disadvantage of poor dispensing accuracy.

[Purpose of the Invention] The present invention was made in view of the above-mentioned conventional problems, and its purpose is to eliminate the sampled sample inside the dispensing nozzle, but only the sample attached to the outer surface of the dispensing nozzle, without removing it. The object of the present invention is to provide a dispensing method that completely eliminates the dispensing process and makes it possible to perform dispensing work with high precision.

[Structure of the Invention] In order to achieve the above object, the present invention provides a dispensing method in which a predetermined amount of a dispensing liquid is sampled using a dispensing nozzle, in which the dispensing nozzle is filled with a diluting liquid, and the tip of the dispensing nozzle is After inhaling a predetermined amount of the sample, a first air layer is formed with the sampling syringe, and the dispensing nozzle is raised, and when its tip is away from the liquid surface of the sample, a small amount of air is sucked in and a second air layer is created. By forming an air layer of After the layer is formed, until the tip of the dispensing nozzle faces the vacuum suction port placed close to the outer surface of the nozzle tip, the adhered sample is removed by suction into the suction port. Then lower the dispensing nozzle again,
The method is characterized in that each of the above steps is repeated for a sample different from the sample.

[Example] Next, a preferred example of the present invention will be described based on the drawings.

In FIG. 5, the pump unit 24 includes a dilution syringe 34 for supplying the dilution liquid 26 into the dispensing nozzle 32 via the three-way valve 28 and piping 30.
A sampling syringe 36 is provided for sampling a sample, which is a dispensing liquid to be described later, and for forming an air layer.

The piston of the sampling syringe 36 is moved up and down by a pulse motor, and its vertical stop position is appropriately set by controlling the pulse motor with a microcomputer.

Furthermore, a vacuum suction port 38 is arranged at the tip of the dispensing nozzle 32 close to its outer surface, and the timing of suction by the suction port 38 is set appropriately.

The operation of the above configuration will now be explained.

First, as shown in FIG. 6A, the dispensing nozzle 32 is filled with the diluent 26, and the sampling syringe 36 forms an air layer 40a at the distal end of the dispensing nozzle 32. Next, as shown in FIG. 6B, after sucking in a predetermined amount of the sample 42, the dispensing nozzle 32 rises, and when its tip is away from the liquid surface of the sample, a slight amount of air is sucked in, resulting in the state shown in FIG. 6C. An air layer 40b is formed as shown. At this time, the dispensing nozzle 32
The sample 42a from when the sample 42 was inhaled is attached to the outer surface of the tip of the sample 4.
2a is sucked into the suction port 38 by vacuum pressure as the dispensing nozzle 32 further rises from the position shown in FIG. 6C. The period during which suction is performed through the suction port 38 is from after the dispensing nozzle 32 samples the sample 42 and rising to form an air layer 40b until the tip of the dispensing nozzle 32 faces the suction port 38. be.

Then, after removing the adhered sample 42a, the dispensing nozzle 32 is lowered again, and then a predetermined amount of a different kind of sample 44 is sampled as shown in FIG. 6D.
Thereafter, as shown in FIG. 6E, an air layer 40c is formed in the same manner as described above. After the air layer 40c is formed, the sample 44a adhering to the outer surface of the nozzle tip is sucked into the suction port 38 and completely removed from the dispensing nozzle 32 during the upward movement of the dispensing nozzle 32.

Similarly, after sampling the serum 46 with high viscosity as the dispensing liquid as shown in FIG.
After that, the serum 46a adhering to the outer surface of the nozzle tip is sucked into the suction port 38 and removed.

As described above, when the samples 42a, 44a and serum 46a adhering to the outer surface of the tip of the dispensing nozzle 32 are suctioned and removed, air spaces 40b, 40 are created under each sample 42, 44 and serum 46, respectively.
c, and 40d are formed, so that a portion of each sample 42, 44 and serum 46 in the sampled dispensing nozzle 32 is not sucked into the suction port 38, and high dispensing accuracy can be obtained. .

[Effects of the Invention] As explained above, the present invention samples a dispensing liquid with a dispensing nozzle, fills an air layer on the open end side of the dispensing nozzle which is the lower side of the dispensing liquid, and then The dispensed liquid attached to the outer surface of the tip of the dispensing nozzle is suctioned by vacuum pressure, so that the dispensing liquid inside the dispensing nozzle is not removed and is attached to the outer surface of the dispensing nozzle. Only the adhering dispensing liquid can be completely removed, and dispensing work can be performed with high precision.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing the dispensing process, Figs. 2 to 4 are explanatory diagrams showing the conventional dispensing method, and Figs. 5 and 6 are explanatory diagrams showing an example of the dispensing method of the present invention. ,
FIG. 5 is a perspective view of the pump unit, and FIG. 6 is an explanatory view showing the dispensing process. 32...Dispensing nozzle, 38...Suction port, 40
a, 40b, 40c, 40d...air layer, 42,
44... Sample (dispensing liquid), 46... Serum (dispensing liquid).

Claims (1)

[Claims] 1. A dispensing method in which a predetermined amount of a dispensing liquid is sampled using a dispensing nozzle, wherein the dispensing nozzle is filled with a diluted liquid, and a first sample is placed at the tip of the dispensing nozzle with a sampling syringe. After inhaling a predetermined amount of the sample, the dispensing nozzle is raised, and when its tip is away from the liquid surface of the sample, a slight amount of air is sucked in, forming a second air layer, and the dispensing By raising the nozzle further, the sample adhering to the outer surface of the tip of the dispensing nozzle can be removed.
The dispensing nozzle samples the sample and rises to the second
After an air layer is formed, until the tip of the dispensing nozzle faces the vacuum suction port placed close to the outer surface of the nozzle tip, the sample adhered to the sample by suction into the suction port. , the dispensing nozzle is lowered again, and the above steps are repeated for a sample different from the sample.