JP2531199B2 - Liquid mixing method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a mixing method for preparing an analytical sample, for example, when a diluent or a reagent is added to and mixed with a sample.

(Prior Art) Conventionally, for the preparation of a sample used for an analytical instrument, for example, when a reagent (or a diluent) is added to a sample and mixed, a sample and a reagent collected in a predetermined amount in a container are aspirated by a syringe, There is a method in which the mixture is again discharged into the container, and if necessary, this suction and discharge are repeated to perform mixing.

(Problems to be solved by the invention) In the conventional mixing method, in order to prevent so-called cross-contamination in the mixing process, the flow path including the nozzle connected to the syringe for sucking the sample and the reagent is filled with the washing liquid. It is normal that That is, when a different type of sample or reagent is sucked, the cleaning liquid is always discharged from the nozzle to clean the flow path and the inside of the nozzle.

Therefore, when a predetermined amount of the sample and the reagent is sucked and discharged while the cleaning liquid is filled in the flow path including the nozzle, the concentration of the sample and the reagent is changed (decreased) due to the mixing of the cleaning liquid and the cleaning liquid.

In order to avoid such changes in concentration due to mixing with the washing liquid, it is possible to form a small amount of air layer as a separator at the interface between the sample and reagent and the washing liquid, but even in this case, the inside of the suction flow path rises with suction. The concentration of the cleaning liquid also drops due to the remaining liquid droplets on the inner wall surface of the flow path. This tendency of concentration decrease is further promoted when the suction and discharge operations are repeated for sufficient mixing (see FIG. 2).

(Means for Solving Problems) The present invention is a mixing method proposed for solving the above-mentioned problems, in which liquids to be mixed collected in a container are introduced into a channel including a nozzle. In the method of mixing by sucking a predetermined amount of liquid from the liquid and then discharging the liquid into the container, the same amount or more of air is sucked before sucking the predetermined amount of liquid into the flow path. Is a liquid mixing method in which a predetermined amount of liquid is sucked and then only a sucked predetermined amount of liquid is discharged.

(Operation) As described above, an air layer space having a volume equal to or larger than a predetermined amount of liquid to be mixed prior to suction is formed in the suction flow path, and thereafter, a predetermined amount of liquid is stored in this space. Is sucked. As a result, it is possible to avoid mixing of the residual liquid droplets on the inner wall surface of the flow path of the cleaning liquid, which rises with the suction of the liquid, with the suction liquid.

(Example) Hereinafter, the liquid mixing method of this invention is demonstrated based on drawing.

FIG. 1 is a channel diagram of an autosampler that is introduced into a liquid chromatograph after a sample is prepared by adding and mixing a reagent and a diluent to the sample.

Flow paths shown, namely nozzle 1, suction flow path 2, syringe 3,
The cleaning liquid flow path 4 is in a state of being previously filled with the cleaning liquid.

To add and mix the reagent to the sample, the solenoid valve 6 is opened and the solenoid valve 7 is closed in this state, and a predetermined amount of the sample is sucked from the sample container SO from the nozzle 1 to the suction flow path 2 by the syringe 3, and the empty container Move to SE.

Next, the nozzle 1 is moved to the position of the cleaning port 5 and inserted into the port 5, and the cleaning liquid is discharged from the nozzle 1 by the syringe 3 to clean the inside of the nozzle 1 and the suction passage 2. To discharge the cleaning liquid, the electromagnetic valve 6 is closed and the electromagnetic valve 7 is opened to suck the cleaning liquid into the syringe 3, and then the electromagnetic valve 6 is opened and the electromagnetic valve 7 is closed to discharge the cleaning liquid by operating the syringe.

After this cleaning, the solenoid valve 6 is opened and the solenoid valve 7 is closed, and the reagent container is closed.
A predetermined amount of reagent to be added from SR is sucked from the nozzle 1 by the syringe 3 and transferred to the container SE in which the sample has been transferred previously. The total amount of the sample and the reagent in the container SE is preferably about 1 ml.

Then, after cleaning the nozzle 1 and the inside of the suction passage 2 again in the same manner as described above, the electromagnetic valve 6 is opened and the electromagnetic valve 7 is closed, and a predetermined amount (for example, 700 μ1) of these sample and reagent is discharged from the container SE to the nozzle 1. The air is sucked into the suction passage 2 through the suction passage 2. In the present invention, prior to this, approximately the same amount or more of the predetermined amount of air is injected by the syringe 3 into the nozzle 1 and the suction passage 2.
Aspirate into.

After the air is sucked in this way, a predetermined amount of the sample and the reagent is sucked, and then the sucked mixed liquid of the sample and the reagent is discharged into the container SE by the amount of the suctioned predetermined amount. As a result, the sample and the reagent are mixed well in the container SE.

If the sample and the reagent are not sufficiently mixed, the suction and discharge of the mixed liquid of the sample and the reagent described above may be repeated. It goes without saying that the concentration of the mixed solution does not change due to this repetition.

The result of comparison between the mixing method of the present invention and the conventional mixing method is shown in FIG.

Sample: Naphthalene 393 mg / methanol 1 l Washing liquid: methanol Sample suction amount for mixing: 700 μl Method A (conventional method): 20 μl of air was sucked prior to sample suction.

Method B (invention method): 700 μl of air was sucked before the sample suction.

Then, the suction and discharge of the sample were repeated to examine the dilution rate (change in concentration) of the sample.

As a result, in the method B of the present invention, there was almost no change in the dilution rate, whereas in the method A of the conventional method, the dilution rate changes (concentration decreases) as the number of times of mixing and discharging the sample is repeated. It was

The mixed liquid of the sample and the reagent thus obtained is again sucked by the nozzle 1 and filled in the sample loop 9 from the injection port 8. And a 6-port valve
10 is switched to the illustrated state, and the sample mixed liquid is introduced into the column of the liquid chromatograph (not shown).

 In addition, 11 is a washing liquid tank.

(Effect) According to the present invention, even when the cleaning liquid is filled in the suction flow path including the nozzle, the liquid mixture is diluted with the cleaning liquid when sucking and discharging the liquid to be mixed into the suction flow path. In particular, there is an advantage that the density does not change even if the number of times of mixing is increased.

[Brief description of drawings]

FIG. 1 is a flow path diagram of an autosampler for carrying out the method of the present invention, and FIG. 2 is a graph showing the results of comparison between the method of the present invention and the conventional method. In the figure, 1 ... Nozzle, 2 ... Suction channel 3 ... Syringe, 5 ... Washing port SO ... Sample container, SR ... Reagent container SE ... Empty container

Claims (1)

(57) [Claims] 1. A liquid to be mixed collected in a container is mixed by sucking a predetermined amount of liquid out of the liquid into a channel including a nozzle and then discharging the liquid into the container. In the method, the same amount or more of air is sucked prior to the suction of the predetermined amount of liquid into the flow path, and then the predetermined amount of liquid is sucked, and only the sucked predetermined amount of liquid is discharged. A liquid mixing method characterized by the above.