JPH04303728A - Sample introducing device - Google Patents

Abstract

PURPOSE:To introduce the required amount of a sample into a thin tube with excellent reproducibility without depending on the viscosity of the sample and the state of the thin tube through which the sample is to be introduced. CONSTITUTION:A specified amount of sample 26 is contained in a sample container 22. The sample introducing end of a capillary 12 is submerged into the sample 26 in the sample container 22. The sample container 22 can be opened to atmosphere and also can be tightly closed with a cap 28 so that the volume of the space in the sample container 22 becomes constant. The sample container 22 is housed in a container 30 whose temperature can be kept at a preset temperature with a thermo-module 24.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for introducing a liquid sample into a thin tube such as an electrophoresis capillary of a capillary electrophoresis device. Capillary electrophoresis equipment is used for highly separated analysis and purification of biopolymers such as proteins and nucleic acids, drugs, and optical isomers, and is particularly suitable for separating components with similar structures and properties. .

0002

[Prior technology] Capillary electrophoresis equipment, which is a high-performance electrophoresis equipment technology, has the advantage of being able to perform high-separation and rapid analysis, and consuming only an extremely small amount of sample. Many automated devices have been announced, and are used for separation analysis and purification of peptides, proteins, nucleic acids, etc.
It is beginning to be widely used as a method suitable for optical resolution, isotope separation, and other separations between extremely similar components. The capillary is filled with running buffer or polymerized gel. After a sample is injected into one end of the capillary, a high voltage is applied across the capillary to cause the sample to migrate, separate, and be eluted and detected from the other end of the capillary.

In some capillary electrophoresis devices, the inner diameter of the capillary is as small as 50 μm or less;
The amount of sample introduced is also very small, usually from several nl to several tens of nl.
It is about l. Therefore, if measurements are to be performed quantitatively and with good reproducibility, a technique for quantitatively introducing an extremely small amount of sample into a capillary is required.

One method for introducing a fixed amount of sample into a thin tube such as a capillary is to make the sample container containing the sample an open system, immerse the sample introduction end of the thin tube in the sample container, and then insert the sample container into the other end of the thin tube. The sample is introduced using the siphon principle by lifting the sample higher than the sample and using the gravity difference.

Another method for introducing a sample is to immerse the sample introduction end of a capillary tube 6 into a sample container 2 containing a sample 4, as shown in FIG. In this method, the sample container 2 is sealed tightly, nitrogen or air is supplied from a cylinder via an open cock 8 to pressurize the sample container 2, and the sample is introduced into the thin tube 6. Yet another method for introducing a sample is to immerse an electrode together with the sample introduction end of a capillary into the sample, apply a voltage between both ends of the capillary, and introduce the sample by electrophoresis.

[0006]

[Problems to be Solved by the Invention] Among the conventional sample introduction methods, in the method of using gravity difference and the method of pressurizing by cylinder pressure, the sample is introduced into a thin tube by keeping the gravity difference, applied pressure, and introduction time constant. However, even if the pressure and pressurization time are kept constant, the speed at which the sample flows into the capillary varies depending on the viscosity of the introduced sample and variations in the inner diameter of the capillary. Variations occur in the amount of sample introduced. Particularly, when the thin tube is about to become clogged, the variation becomes noticeable. Furthermore, when a sample is introduced by electrophoresis, it is easily affected by the viscosity of the sample and the substances contained in the sample.

An object of the present invention is to provide a sample introduction device that can introduce a desired amount of sample into a capillary with good reproducibility, regardless of the viscosity of the sample or the condition of the capillary into which the sample is to be introduced. It is something.

[0008]

[Means for Solving the Problems] In the present invention, a sample container is hermetically sealed, and the sample is introduced into a thin tube by utilizing thermal expansion of air in the sample container. Therefore, in the present invention, a sample which has a constant volume of space when containing a liquid sample, and which can be in either a closed state or an open state when the sample introduction end of the thin tube into which the sample is to be introduced is immersed in the sample. It includes a container and a heating means for changing the temperature of the sample container. After putting a certain amount of sample into a sample container and setting the temperature to a constant temperature, the sample introduction end of the capillary tube is immersed in the sample, the sample container is sealed, and the other end of the capillary tube is opened to the atmosphere, and the sample is heated by heating means. A sample is introduced into the capillary by changing the temperature of the container to a predetermined temperature.

[0009]

[Operation] When the air in a sealed sample container is heated to a certain temperature, the volume of the air in the sample container expands by a certain percentage. If the capillary is immersed in the sample in the sample container, the sample corresponding to the expansion volume will be introduced into the capillary. The speed at which the sample is introduced into the capillary is affected by the viscosity of the sample liquid and the inner diameter of the capillary, but the amount of sample introduced is determined by the volumetric expansion of the air in the sample container, so set the introduction time sufficiently long. If this is done, the amount of sample introduced will not be affected by the viscosity of the sample liquid or the inner diameter of the capillary.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 schematically shows a capillary electrophoresis apparatus as an example to which the present invention is applied. 1
2 is a capillary for electrophoresis which is a thin tube, and capillary 1
Both ends of the capillary 12 are immersed in the electrophoresis buffer solutions 14 and 16, and a voltage for electrophoresis is applied between both ends of the capillary 12 from the high-voltage power supply 18, so that the sample introduced into one end of the capillary 12 is electrophoresed and separated. It will be done. The separated components are detected by detector 20. In order to introduce a sample into the capillary 12, a sample introduction device of the present invention is provided which includes a sample container 22 and heating means 24.

As shown in an enlarged view in FIG. 2, the sample introduction device stores a certain amount of liquid sample 26 in a sample container 22, and the sample introduction end of the capillary 12 is immersed in the sample 26 in the sample container 22. be done. The sample container 22 can be opened to the atmosphere, or can be sealed with a lid 28 so that the volume of the space inside the sample container 22 is constant. Sample container 22
The sample container 22 may be sealed and opened by opening and closing the lid 28, or a tube with an opening/closing cock may be attached to the lid 28, and the opening/closing cock may be opened and closed.

The entire sample container 22 is housed in a container 30 that can be maintained at a constant temperature by a heater or thermo module 22 as heating means. The thermo module 24 is controlled by a regulator (not shown) to maintain a set temperature.

Next, the operation of introducing a fixed amount of sample into the capillary 12 according to this embodiment will be explained. First, the sample container 22 is opened, a certain amount of the sample 26 is put into the sample container 22, the sample introduction end of the capillary 12 is immersed in the sample 26, and the entire sample container 22 is maintained at a certain temperature. At this time, it is necessary to maintain not only the sample 26 but also the air inside the sample container 22 at a certain temperature. Next, the sample container 22 is sealed by a method such as closing the lid 28, and the thermo module 24 is closed.
, the temperature is increased by a certain amount from that certain temperature. At this time, it is important that the sample container 22 is sufficiently sealed and that the heated temperature difference is correct to the set temperature difference. As a result, as shown in FIG. 3, the sample container 22 is heated by a constant temperature from the state (A) before heating.
The air inside expands, and the sample 26 is introduced into the thin tube 12 by the volume a of the expanded air, as shown in (B). 26
a is a sample introduced into the capillary 12; At this time, the sample 26 is also heated and expands thermally, but the thermal expansion of the liquid is very small compared to the thermal expansion of air and can be ignored.

[0014]

Effects of the Invention: In the present invention, the sample is introduced into the capillary by the amount of air expansion in the sealed sample container, so when the sample is introduced into the capillary, the viscosity of the sample solution and the clogging of the capillary are reduced. Although it affects the introduction speed, the amount of sample introduced into the capillary is determined by the volume of air expanded in the sample container, so by setting the sample introduction time sufficiently long, the amount of sample introduced into the capillary is determined by the volume of air expanded in the sample container, regardless of the introduction speed. It is determined by the volume of the space and the difference in temperature, and if the conditions are kept constant, a constant amount of sample will always be introduced, increasing quantitative performance. Furthermore, the amount of sample introduced can be arbitrarily set by changing the temperature difference during heating.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a capillary electrophoresis device as an example to which the present invention is applied.

FIG. 2 is a schematic cross-sectional view showing a sample introduction device of one embodiment.

FIG. 3 is a sectional view showing the sample introduction operation of the same embodiment.

FIG. 4 is a schematic cross-sectional view showing a conventional sample introduction method.

[Explanation of symbols]

12 Capillary for electrophoresis 22 Sample container 24 Thermo module 26 of heating means
Sample 28 Lid

Claims (1)

[Claims] [Claim 1] A tube having a fixed volume of space containing a liquid sample, and capable of being in either a closed state or an open state with the sample introduction end of the tube into which the sample is to be introduced immersed in the sample. The sample container includes a sample container and a heating means for changing the temperature of the sample container, and the sample introduction end of the thin tube is immersed in the sample after a certain amount of sample is placed in the sample container and the temperature is set at a constant temperature. A sample introduction device in which the temperature of the sample container is changed to a predetermined temperature by the heating means with the sample container being sealed and the other end of the capillary tube being open to the atmosphere, and the sample is introduced into the capillary tube. .