JPS6232365A - Method for sucking liquid sample in analyzing instrument - Google Patents

Abstract

PURPOSE:To prevent the diffusion of a cleaning liquid to an analyzing sample and the spread of the analyzing sample by sucking a gaseous phase and a small amt. of the sample of the same kind as liquid sample and further sucking the gaseous phase then sucking a prescribed amt. of the liquid sample. CONSTITUTION:The cleaning liquid 1 in a piping is fed and the specified amt. of air 2a is sucked after the analysis of the previous liquid sample. The sample 3 which is of the same kind as the liquid sample to be used for the analysis is then sucked at the min. amt. required to remove the liquid 1 and to prevent the dilution of the liquid sample to be sucked for the purpose of the analysis and further the specified amt. of the air 2b is sucked. The sample 3 of the min. amt. required for the analysis is sucked and further the air 2c is sucked. The mixing of the liquid 1 and the sample 3 is thus prevented by the air 2a and further the mixing of the sample 3 mixed with the liquid 1 and the sample 4 for analysis is prevented by the air 2a. The dilution of the sample 4 for analysis is prevented as well. Since the sample 4 is sealed by the air 2b and c, the spread thereof is suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a method for injecting a liquid sample for analysis into a sample injection section or a sample analysis section consisting of a liquid flow path, for example, in a liquid chromatography analyzer. It concerns a method of injecting a sample.

Conventional Technology As is well known, liquid chromatography is currently a popular analysis method for liquid samples, and is used not only in science and engineering, but also in related fields such as pharmacy, medicine, agriculture, biochemistry, and more. Its usefulness has also been recognized in its application fields.

The basic components of this liquid chromatography include a liquid feeding section, a sample injection section, a separation section, a detection section, and a recording section. This configuration will be explained based on FIG. 4. The sample injection section consists of a six-way valve 6 and a sample loop 7.
The six-way valve 6 has boats P1 to P6, and a sample loop 7 is connected between the boats P3 and P6. A needle 9 for aspirating a liquid sample is connected to the boat Pi through a thin tube 8, and this needle 9 is inserted into a sample storage section 11 containing an analysis sample 10 when aspirating an analysis sample. One valve of a three-way valve '12 is connected to the boat P5, and the other valves of this three-way valve '12 each have a valve connected to the boat P5. Microsyringe 13 and washing 81114 are connected. Furthermore, a male medium tank 16 is connected to the boat P1 via a liquid feeding section 15, and a separation section 17 and a detection section 18 are sequentially connected to the boat P2. is connected to the abandoned eastern part.

Next, to explain the operation of this device, the six-way valve 6
is in the loaded state, the main valves 6 are Pi-P2, P-3-Pi, P5-P6, respectively, as shown by solid lines.
The three-way valve 12 connects the microsyringe 13 and the boat P5 of the hexagonal pulp 6. As a result, the eluent stored in the solvent tank 16 is transferred to the liquid feeding section. 15, the baud h P 1 of the six-way valve 6
The liquid is sent to the vessel, passes between the boats P1 and P2, and constantly flows to the separation section 17. A liquid sample 10 for analysis is passed through the needle 9.1B tube 8 by the microsyringe 1-3, and is then transferred to the boat 1-Pi, P3, and then to the sample loop 7 and the boat P.
6. P5 is sucked to flow. In this state, the sample loop 7 is filled with a liquid sample for analysis.

On the other hand, when the six-way valve 7 is in the inject state, the balls L- are Pl-P6 and PI, respectively, as shown by the broken lines.
P3, Pi-P5 are connected, and the sample for analysis in the sample loop 7 is swept into the separation section 17 via the bows 1-P3, P2 by the eluent sent through the bows 1-Pi, P6. Then, the liquid sample is analyzed. In this state, the thin tube J and the needle are washed by sending the washing liquid to the bowl 1-P5 using the microsyringe 13.
≧Can be done.

This II is employed not only in liquid chromatography but also in other liquid sample analysis methods.

FIG. 5 shows an example of a liquid sample analyzer that does not have a sample injection part, unlike the apparatus shown in FIG.
The connected thin tube 8 is connected to the sample analysis section 1 having a liquid flow path 18a.
8.

The @ end of this sample analysis section 18 (this is the 5 at one end of the three-way valve 12
! The liquid sample 10 for analysis is transferred from the sample storage section 11 by the microsyringe 13 through the needle 9 and the thin tube 8 to the liquid channel 18al of the sample analysis section 18.
: Guide. This sample analysis section 18 includes an analysis device (not shown) for analyzing a liquid sample by optical means or the like.
) are provided. Further, by sending the cleaning liquid from the cleaning liquid tank 1.4 to the sample analysis section 18 via the three-way valve 12, the inside of the liquid flow path 18a, the thin tube 8, and the needle 9 can be cleaned.

Recently, these devices have been controlled by centralized computer control, etc., and have become capable of automatically and unmanned processing, including suction, injection, analysis, and detection of liquid samples, as well as data analysis processing. . In connection with this automatic processing, an automatic injection system has been developed that automatically injects a liquid sample for analysis into a sample injection section and also automatically cleans the needle, piping, etc. prior to this injection.

Problems to be Solved by the Invention By the way, the automatic injection device mentioned above has problems with the reproducibility of the injected candy for analysis samples, the constant electrostatic property, and the 8!
4. It is important to minimize the amount of waste and waste of samples. However, if we place importance on the reproducibility of the sample injection section, that is, constant density, sample wastage is unavoidable, and if we try to minimize sample consumption, the reproducibility of the sample injection section will be impaired. be.

To be more specific, when injecting a sample, a cleaning liquid is injected into the needle, piping, and even into the sample injection part until it reaches Y, in order to wash and remove a previously used liquid sample of, for example, another type. However, in this cleaning method, a layer of cleaning liquid remains attached to the inner wall of a thin tube such as a pipe, so that when a new sample is injected, the remaining cleaning liquid dilutes the sample, impairing the stability of the sample. Eliminate this phenomenon and ensure quantitativeness 1
Instead, a method can be considered to remove and cover the remaining cleaning liquid adhering to the inner wall of the m-tube at the leading end of the sample to be injected.

However, in this method, an extra and large amount of sample is injected to remove the residual washing solution, so wasting of the sample is avoided. The remaining cleaning liquid absorbed at the leading end of 1 is continuously diffused to the rear end of the sample.
Strictly speaking, even the sample in the rear part, which almost matches the sample concentration, is diluted with the remaining washing solution, and in the analysis of liquid samples that also performs breeze analysis (there is a difference in quantitative quality. If this is minimized, a problem arises in that when the sample is aspirated, it spreads inside the pipe, and a part of the aspirated sample is not injected into the sample injection section.This invention solves the first problem mentioned above. The basic purpose is to ensure the quantitative performance of the analytical liquid sample and to minimize the consumption of the sample when injecting the analytical liquid sample into a single-person section or a test analytical section (which consists of a liquid flow path). The present invention provides a method for aspirating adult samples that can be aspirated.

Means for solving the problem, that is, the present invention is a method of injecting a predetermined amount of liquid sample for analysis into a sample injection section or sample analysis section consisting of a liquid flow path in a method in which 11 people inject a liquid sample F1 for analysis. First, a preliminary suction step is carried out once or twice, in which the gas phase J-3 and a small amount of the same type of sample as the liquid sample are suctioned in order, and then the gas phase is further suctioned, and then the analysis is carried out. It is characterized by aspirating a liquid sample of a predetermined amount S.

A cleaning step of primarily suctioning the gas phase and cleaning liquid may be added instead of the preliminary step or prior to the preliminary step.

According to this invention, the preliminary step 1. : The cleaning liquid remaining on the inner wall of the liquid flow path of the piping tube, sample injection section, or sample analysis section is removed by the liquid sample sucked in the preliminary step. Moreover, the gas phase sucked in last in the preliminary step prevents the cleaning liquid from diffusing from the sample mixed with the cleaning liquid into the analytical liquid sample that is injected later, and also prevents the analytical sample from spreading. .

33. Complete cleaning can be achieved by performing a cleaning process in which the gas phase and the cleaning liquid $i are sequentially suctioned once or twice, prior to or instead of the preliminary suction process.

Note that if the gas phase is air, the above effects can be obtained with an inexpensive and simple configuration.

Furthermore, if this application is applied to an automatic injection device, sample injection and cleaning of piping tubes and liquid channels can be automatically processed, and separation, which is another component of Analysis V41f, can be performed automatically.
Accurate and
l! Automatic analysis can be performed easily, and it is also possible to immediately analyze samples of other types after analyzing a sample from one bar.

EXAMPLE An example of the present invention will be described below with reference to FIG. FIG. 1 is an enlarged view of the sample loop and six-way valve 6 shown in FIG. 4 and their surrounding areas.

After analyzing the previous liquid sample, the cleaning liquid 1 is fed to the hexagonal valve 6, the thin tube 8, and even the needle 9 in order to clean the inside of the piping system. When the next liquefied sample is aspirated, the six-way valve 6 is in a loaded state, and a constant amount of air 2a is aspirated from the microsyringe 13 from the tip of the needle 9. Next, a sample 3 of the same type as the liquid sample to be used for analysis and the minimum amount of silver necessary to prevent the removal of the washing liquid and dilution of the liquid sample that is then aspirated for analysis is aspirated, and a certain amount of air 2b is then aspirated. Suction. Next, the minimum amount of liquid sample 4 necessary for analysis is aspirated, and further air 2C is aspirated.

When the liquid sample 4 for analysis is drawn into the six-way valve 6, the number of points is sufficient to at least fill the sample lugua. mi
The cleaning liquid remaining on the inner wall of the liquid flow path is absorbed by the liquid sample, and mixing of the cleaning liquid 1 and the sample 3 is prevented by the air 2a. Furthermore, the air 2b prevents the sample 3 and the sample 4 mixed with the cleaning liquid from being mixed, thereby preventing dilution of the liquid sample for analysis. Also, sample 4 has air 2b and 20
Since it is sealed with a seal, the spread is suppressed and the quantitative quality of the liquid sample for analysis is ensured.

When the six-way valve 6 is in the injection state, the solvent tank 16
Since the eluent stored in is sent to the port P1 by the liquid sending section 15, the sample 4 injected into the sample loop 7 passes through the boat P2 and is all pushed out to the separation section 17.

Roughly speaking, when the six-way valve 6 is in the injection state, the cleaning liquid that has already been sucked out is pushed out from the port 5 to the boat 4 and discharged from the needle 9 to clean the piping tube and needle. If so, connect the three-way valve to cleaning liquid tank 1.
4 to suck the cleaning liquid, and then communicate with the six-way valve side to push out the cleaning liquid to the needle side.

Next, an experiment was conducted to compare the degree of dilution of the liquid sample between the embodiment of the present invention and the case where the liquid sample was injected by the conventional method.

Note that in these comparisons, a sample loop with a volume of 50 tll was used.

In an embodiment of the invention, 2μ! After aspirating 15 μl of air into the same type of liquid as the analytical liquid sample, 2 μl of air was injected, and then 15 μl of the liquid sample was injected into the analytical liquid sample.
and 80 μk of air were injected sequentially.

On the other hand, in the conventional example, only the liquid sample for analysis is yμ! The leading end of the liquid sample was sucked up to absorb the fine snow for the pipe and the cleaning liquid adhering to the inside of the liquid flow path, and the end of the liquid sample was used as a liquid sample for analysis.

Figures 2 and 3 show analytical liquid samples 1''4arj1 when samples were injected xμβ, y, and u1 in each comparative example. In each figure, the horizontal axis represents The Ijl axis shows the peak height value of the analytical liquid sample. In the example of this invention, when X was set to 65 (not shown), no dilution of the analytical liquid sample was observed. In other words, as shown in Figure 2, regardless of the increase in
was sufficient.

On the other hand, in the conventional example, as shown in Figure 3, the 'f1 degree of the liquid sample for analysis was measured while increasing y starting from 145, but when V reached 280, even if it was 63, the concentration remained constant. It was observed that the concentration increased as y increased. The results of these comparative examples are shown in Table 1.

Table 1 ■ In other words, in the embodiment of this invention, 80 μl of the sample was sufficient, whereas in the conventional example, 50 μl of the sample loop volume was sufficient.
Even though a sample of 280 μm, which has a volume more than twice that of the previous one, was used, the quantitative properties of the sample were not satisfied. From this comparative example, it was found that the present invention was at least 3.5 times more efficient than the conventional example in terms of sample consumption.

Furthermore, column: Silica 0DS (4,6φ x 150 pieces I)
As a result of examining the reproducibility of the peak area of the sample eluted from the separation section using methanol as a solvent and pyrene as a solvent, good reproducibility was obtained with a cvm of 0.16%.

In this example, the gas phase and the liquid sample of 9 candy were injected once, but it is also possible to repeat the injection as many times as desired, and the gas phase and the cleaning liquid were injected before or instead of this step. It is also possible to perform the injection step once or more than once. Further, the gas phase is not limited to air, and any suitable gas can be used depending on the type of gas, but air can be used to simplify the structure.

Further, in this embodiment, a gas phase of a predetermined H was sucked after injection of a liquid sample for analysis, but the above-mentioned suction of the gas phase is not necessarily necessary for the present invention. However, by suctioning the gas phase, the liquid sample for analysis is sealed with the previously injected gas phase, so that spreading of the liquid sample can be more effectively suppressed.

Furthermore, although this embodiment has been described with reference to a case where the injection section is applied to liquid chromatography consisting of a six-way valve and a sample loop, the application is not limited to liquid chromatography; It is not limited to this. Furthermore, the present invention is not limited to the above-mentioned application example, but can also be applied to analysis without a sample injection section.

Effects of the Invention As explained above, the present invention eliminates the need to consume a liquid sample for analysis in a method for injecting a liquid sample for analysis into a sample injection section or a sample analysis section consisting of a liquid flow path. It is possible to quantitatively obtain a liquid sample for analysis that is minimally diluted with a washing solution.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of an embodiment of the present invention, and Fig. 21fi is a sample 'a' for suction of an analytical sample in the embodiment of the present invention.
Figure 3 is a graph showing the degree of sample aspiration in the conventional method; Figure 4 is a schematic diagram of the conventional method for analyzing liquid clot gelatin; Figure 5 is a diagram showing other methods. This is a schematic diagram of the analysis technique U. 1...Cleaning liquid, 23.2'n, 2c...Air, 3...Small liquid sample, 4...Liquid sample for analysis 11゜Applicant JASCO Corporation Agent Patent Attorney Agriculture 1 ) Takehisa (11 people) Figure 3

Claims (3)

[Claims] (1) In a method of injecting a liquid sample for analysis into a sample analysis section consisting of a liquid flow path, before injecting a predetermined amount of liquid sample for analysis, a gas phase and a small amount of the same type of sample as the liquid sample are injected into the gas phase. Suction of a liquid sample in an analytical device characterized by performing a preliminary suction step of suctioning in that order once or twice, then further suctioning a gas phase, and then suctioning a predetermined amount of liquid sample for analysis. Method. (2) A method for aspirating a liquid sample in an analyzer according to claim 1, characterized in that, prior to the prognostic suction step, a cleaning step of sequentially suctioning a gas phase and a cleaning liquid is performed once or twice or more. . (3) A method for sucking a liquid sample in an analyzer according to claim 1 or 2, characterized in that air is used as the gas phase.