JPH04303758A - Capillary electrophoresis device - Google Patents

Abstract

PURPOSE:To eliminate a washing process of electrodes without dipping the electrodes in specimen solution and prevent pollution through the electrodes from producing. CONSTITUTION:Electrode rods 28 made of insulating material protecting electrodes 22 are moved with the aid of the rotation of a pulse motor 24 so that the electrodes 22 can be moved between a certain position near a capillary 2 and another position apart from the capillary 2. The end part of the specimen injection side of the capillary 2 is fixed at an infection block 6 with the use of a seal member 4, a washing bottle 12 placed on a turn table 10 and the like are pushed up by the use of a lift and airtightly sealed to supply, pressure and inject inert gas into it.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a capillary electrophoresis device in which a sample is injected into one end of the capillary, both ends of which are immersed in respective electrophoresis buffer solutions, and an electrophoresis voltage is applied between both ends of the capillary. 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 used usually has an inner diameter of 50 to 100 μm and a length of 2
0 to 100 cm, therefore the volume is 1 to 2
It is μl. The capillary is filled with running buffer or polymerized gel. After a sample of nl order is injected into one end of the capillary, 30k is applied between both ends of the capillary.
A high voltage of about V is applied to cause the sample to migrate, be separated, and then eluted from the other end of the capillary and detected.

[0003] Conventional capillary electrophoresis devices are operated with the end of the capillary and the electrode paired, and when injecting a sample, the end of the capillary and the electrode are simultaneously injected into the sample solution with their tips facing downward. After sample injection, both the capillary end and the electrode are immersed in the electrophoresis buffer solution.

0004

[Problems to be Solved by the Invention] There are several methods for injecting a sample into a capillary. Electrodes are required when electrically injecting a sample into a capillary, but methods in which the sample is injected using differential pressure by pressurizing the sample injection side of the capillary and reducing pressure at the other end No electrodes are required during injection. However, in conventional capillary electrophoresis devices, the electrodes are immersed in the sample container together with the capillary even when the sample is not electrically injected, which can be a major source of contamination unless a cleaning step is performed for the electrodes before analysis. The present invention aims to eliminate the cleaning process of the electrodes by preventing the electrodes from being immersed in the sample solution in a capillary electrophoresis device that uses a differential pressure sample injection method, and to prevent contamination from occurring through the electrodes. It is.

[0005]

[Means for Solving the Problems] In the present invention, a moving mechanism is provided on the sample injection side for separating the capillary and the electrophoresis voltage application electrode from each other and repositioning them to their original positions;
A sample supply mechanism that pushes up a selected container at the sample injection position and immerses the capillary end in the liquid in the container is provided, and the container is hermetically sealed with the capillary end on the sample injection side immersed in the container. An injection mechanism is provided for injecting the liquid in the container into the capillary using a differential pressure by pressurizing the capillary or reducing the pressure at the other end of the capillary.

[0006]

[Operation] When injecting a sample, the electrode is isolated from the capillary end on the sample injection side, and only the capillary end is immersed in the sample solution. Sample solution does not adhere to the electrode. When cleaning the capillary, only the injection end of the capillary is immersed in the cleaning liquid. After the sample is injected, the electrode and the capillary injection end are brought close together and positioned at a predetermined position, and both are immersed in the electrophoresis buffer solution to begin analysis. Since the electrode is immersed only in the running buffer, there is no risk of contamination.

[0007]

Embodiment FIG. 1 shows the state during sample injection in one embodiment, and FIG. 2 shows an enlarged view of the sample injection side during analysis. The end of the capillary 2 on the sample injection side is a sealing member 4.
It is fixed to the injection block 6 by. A sealing member 8 is also provided on the lower side of the injection block 6, and a cleaning bottle 12, sample bottle 14, or migration buffer bottle 16 placed on the lower turntable 10 is selected, and a lifting mechanism using a ball screw, air cylinder, etc. When pushed up by the piston 18, the injection block 6 is airtightly sealed by the seal member 8 on the lower surface. The turntable 10 is rotated by a motor 48 and a selected sample bottle or the like is positioned at a predetermined position. Inert gas is supplied to the injection block 6 via a solenoid valve 20 that is opened and closed by a solenoid, and the pressure inside the cleaning bottle or sample bottle is hermetically sealed and supplied with inert gas. Pressure gauge 21 to monitor
is attached via an injection block.

A gear 26 attached to the rotating shaft of the pulse motor 24 moves the electrode 22 so that the electrode 22 can move between a predetermined position close to the capillary 2 and a position away from the capillary 2 on the sample injection side. The electrode 22 is engaged with a rack 30 attached to an insulating electrode rod 28 that protects the electrode 22, and the rotation of the pulse motor 24 causes the electrode 22 to move in the horizontal direction. In order to position the electrode 22 at a predetermined position, the electrode rod 28 is provided with a protrusion 32, and a positioning sensor 34 for detecting the protrusion 32 is fixed to the support. The position where the protrusion 32 is detected by the positioning sensor 34 is a predetermined position where the electrode 22 and the capillary 2 are close to each other. The electrode rod 28 is made of a highly abrasion-resistant polyacetal-based insulating resin (trade names include Delrin and Duracon, for example), and all members around the electrode 22 have an insulating structure.

A detection cell block 36 is provided on the detection side of the capillary 2, and a detector optical system 38 is provided. On the detection side, the migration buffer solution container placed on the turntable 10 is pushed up by the piston 40 of the elevating mechanism, and the end of the capillary is immersed in the migration buffer solution.

The electrode 22 on the sample injection side is connected to a high-voltage power supply 42, and the electrophoresis buffer solution on the detection side is grounded, so that an electrophoresis voltage is applied between both ends of the capillary 2. A driver circuit 46 that drives the movement of the electrode 22 by the pulse motor 24, a high-voltage power supply 42, the operation of the motor 48 that rotates the turntable 10, and a piston 18 that is driven by an elevating mechanism.
, 40, pressure control by inert gas supply during sample injection and cleaning, etc., a controller 44 is provided.

Next, the operation of this embodiment will be explained. In capillary electrophoresis, in order to maintain separation reproducibility and quantitative performance, it is necessary to clean the inside of the capillary 2 to maintain a uniform condition on the inside of the capillary. When cleaning,
As shown in FIG. 1, the electrode 22 is isolated from the capillary 2, and the washing liquid container 12 is first selected by rotation of the turntable 10, and the piston 18
can be raised by On the detection side of the capillary, a bottle for disposal is selected and pushed up by the piston 40 to receive the detection side end of the capillary 2 . In this state, the electromagnetic valve 24 is opened for a predetermined period of time, pressure is applied to the washing bottle 12, and washing liquid is flowed into the capillary 2 to perform washing. For washing, a running buffer solution may be used as a washing solution.

When the cleaning operation is completed, the cleaning bottle 12 is lowered onto the turntable 10 on the sample injection side. Next, the sample bottle 14 is selected by the turntable 10, and the piston 1
8 to push it up to the sealing surface of the injection block. Then, the solenoid valve 20 is opened and a specified volume of the sample is injected into the capillary 2. During this time, the electrode 22 is located away from the capillary 2. In this state, the high voltage power supply 42
Provide an interlock mechanism to ensure that it never activates.

After the sample injection is finished and the sample vial 14 is lowered onto the turntable 10, the vial 16 of running buffer is selected and the electrode 22 is moved by the pulse motor 24 until it reaches a precisely defined position next to the capillary 2. is driven and electrode 2
2 moves in the horizontal direction and comes to rest at a prescribed position by the action of the positioning sensor 34, pulse motor 24, and controller 44. Here, the interlock mechanism of the high voltage power supply 42 is released. Then, as shown in Figure 2, bottle 1 of the running buffer solution is added.
6 is pushed up by the piston 18, the electrode 22 and the capillary injection end are immersed in the migration buffer, and the capillary 2
The detection end of is also immersed in the running buffer. Then, a high voltage is applied and the analysis begins.

[0014] Analysis can also be started after the capillary is immersed in a washing bottle of running buffer solution in order to wash away the sample adhering to the outer wall of the capillary after sample injection. After the analysis is completed, the electrode 22 is moved away from the vicinity of the capillary again, and the sample injection end of the capillary 2 is immersed in the cleaning liquid to be cleaned again. Next, the sample injection end of the capillary 2 is inserted into another sample bottle, the sample is injected into the capillary end in the same manner as above, and the electrode 22 is slid to a specified position and immersed together with the capillary 2 in the electrophoresis buffer solution to increase the electrophoresis voltage. is applied. Even in these continuous operations, the electrode 22 is only immersed in the electrophoresis buffer solution.

In the embodiment shown in FIG. 1, the electrode 22 is moved in the horizontal direction, but the invention is not limited to this, for example, the electrode 22 is moved in the horizontal direction.
2 may be moved up and down to move away from the sample injection end of the capillary 2, or may be moved away by rotational movement.

In FIG. 3, the position of the electrode 22 is fixed and the sample injection end of the capillary 2 is moved, contrary to the embodiment shown in FIG. This shows an embodiment in which the two are separated from each other. In FIG. 3, the electrode 22 is fixed, and the injection block 4 is attached to the tip of a capillary support arm 50 that is rotated by a pulse motor 52.
is fixed to the injection block 6 by a seal member 4. A seal member 8 forming a sealing surface is provided on the lower surface of the injection block 6. A piston 18a of a first elevating mechanism that pushes up the cleaning bottle 12 and sample bottle from the turntable 10 at the lower part of the capillary 2 separated from the electrode 22.
and a piston 18b of a second elevating mechanism that pushes up the migration buffer bottle 16 at a position below the electrode 22 during analysis.
is provided. In order to pressurize the injection block 6 and inject the cleaning liquid or sample into the capillary 2, a mechanism is also provided that supplies inert gas through a solenoid valve 20 that is opened and closed by a solenoid to pressurize the inside of the cleaning bottle or sample bottle. There is. A pressure gauge 22 for monitoring pressure is provided in the inert gas supply path.

Next, the operation of the embodiment shown in FIG. 3 will be explained. In order to clean the inside of the capillary 2, the capillary support arm 50 is positioned at position a shown by the solid line in the figure, and the capillary 2 is separated from the electrode 22. A cleaning liquid bottle 12 is selected at the sample injection end of the capillary 2, is pushed up by the piston 18a, contacts the sealing surface of the injection block 6, and is hermetically sealed, and an inert gas is supplied into the bottle and heated. A specified pressure is applied for a specified period of time, and the cleaning is carried out. After the cleaning operation is completed, the sample bottle is selected and pushed up by the turntable 10, the inside of the sample bottle is pressurized, and a specified volume of sample is injected into the capillary 2.

After the sample is injected, the capillary support arm 50 is rotated by a precise angle by the stepping motor 52 to the position indicated by the broken line (the position where the capillary 2 approaches the electrode 22).
Move to b. A bottle 16 of the electrophoresis buffer solution is selected at a position below the electrode 22, and is pushed up by the piston 18b so that the capillary 2 and the electrode 22 are immersed in the electrophoresis buffer solution, and an electrophoresis voltage is applied from the high-voltage power supply to start the analysis. . After sample injection, in order to wash away the sample adhering to the outer surface of the capillary, it is desirable to provide an operation in which the washing bottle is raised at position a to immerse the capillary before moving the capillary support arm to position b. In the embodiment of FIG. 3, the capillary 2 is preferably translated horizontally. This is because when the capillary 2 is moved up and down, the solution in the capillary may move inadvertently due to the siphon principle.

In addition to the mechanisms mentioned in the embodiments, various modifications can be made to the present invention. For example, although the capillary 2 is pressurized in order to inject the cleaning liquid and the sample, the detection end side of the capillary 2 may be depressurized and the cleaning liquid and the sample are injected into the capillary 2. In order to accurately position the electrodes and capillaries to be moved to their original positions, in the embodiments a positioning sensor is provided or a stepping motor is used, but other positioning mechanisms may be used. In addition, in the example, the same turntable is used for selecting sample bottles, etc. on the sample injection side and the detection side, but the turntable is different for the sample injection side and the detection side. It can also be used as a turntable. Further, although the sample bottle and the like are raised and lowered by using a piston to raise and lower the bottle itself, a mechanism in which the entire turntable is raised and lowered may also be used.

[0020]

According to the present invention, since the electrode and the capillary are separated from each other when a sample is injected, the electrode is not immersed in the sample, and contamination by the electrode can be avoided. Further, in the sample injection step and the capillary cleaning step, since the electrode is separated from the capillary, a structure in which only the end of the capillary is hermetically sealed becomes simple. In embodiments in which the electrode moves, an interlock mechanism linked to the movement of the electrode can be provided such that when the electrode is separated from the capillary, the high voltage power source is automatically turned off.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view showing one embodiment.

FIG. 2 is a vertical cross-sectional view during analysis showing the sample injection side of the embodiment in FIG. 1 in detail.

FIG. 3 is a diagram showing another embodiment, in which (A) is a plan view on the sample injection side, and (B) is a vertical sectional view thereof.

[Explanation of symbols]

2 Capillaries 4, 8 Seal member 6 Injection block 10 Turntable 12 Washing bottle 14 Sample bottle 16 Running buffer bottle 20
Solenoid valve 22 Electrodes 24, 52 Pulse motor 34 Positioning sensor 42 High voltage power supply 44 Controller

Claims (1)

[Claims] Claim 1: In a capillary electrophoresis device in which a sample is injected into one end, both ends of the capillary are immersed in respective electrophoresis buffer solutions, and an electrophoresis voltage is applied between both ends of the capillary. A moving mechanism for separating the application electrode from each other and repositioning it to the original position, and a sample supply mechanism for pushing up a selected container at the sample injection position and immersing the capillary end in the liquid in the container, An injection mechanism that, with the end of the capillary on the sample injection side immersed in the container, airtightly seals the container and pressurizes it, or depressurizes the other end of the capillary and injects the liquid in the container into the capillary using differential pressure. A capillary electrophoresis device characterized by being provided with.