JPH0587778A - Capillary electrophoretic device - Google Patents

Abstract

PURPOSE:To know the washing state of capillary on the way of washing. CONSTITUTION:An electrode 2 and one end of a capillary 1 are inserted in a vial 9 in order to supply a washing solution or a buffer solution into the capillary 1 and the vial 9 is hermetically closed to be pressurized. A voltage contact 2 or a flow voltage measuring contact 21 comes into contact with the electrode 2 and the electrode 3 on the other end side of the capillary 1 is connected to a high voltage power supply 5 or a voltage measuring device 25 through a changeover relay 6. The washing solution in the vial 9 is pressurized to be allowed to flow in the capillary 1 and the flow voltage accross the electrodes 2, 3 is measured by the voltage measuring device 25. When the flow voltage becomes a steady state, washing operation is completed.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a capillary zone electrophoresis apparatus for separating and analyzing charged substances such as amino acids, proteins, and nucleic acids, and separation and analysis including neutral substances by interaction with components contained in a buffer solution. The present invention relates to a capillary electrophoresis device that is a generic term for both interfacial conductivity chromatography.

[0002]

2. Description of the Related Art In a capillary electrophoresis apparatus, a detector detects a substance electrophoresing in the capillary and a neutral substance moving by an electroosmosis method by a voltage applied to both ends of the capillary, and a data processing device from the detection signal. The elution time of each peak is detected by and the components of each peak are identified from the elution time. Since the mobility of each peak component is determined by the type of component and the situation in which it is placed, the retention time is an index for identification as in the case of chromatography. Moving velocity Vi of each component in capillary electrophoresis
Is given by Vi = ( Mi + Me.o) E where E is the strength of the electric field, Mi is the effective mobility of the ion species i as an ion, and Me.o is the mobility of the electroosmotic flow due to the electric double layer on the inner surface of the capillary. .. The mobility Me.o of the electroosmotic flow changes depending on the surface state of the inner surface of the capillary. M
Since the ion elution time changes when eo changes, various cleaning methods such as a method using an alkaline solution, a method using water, and a method using a buffer solution have been proposed as the cleaning method in order to sufficiently clean the inner surface of the capillary. ing.

[0003]

Since the state of the inner surface of the capillary is not known during the cleaning of the capillary, a method is adopted in which cleaning is performed under certain conditions and then an actual analysis is performed to confirm whether the cleaning was sufficient. ing. Therefore, the cleaning efficiency is poor. If the washing state of the capillaries can be known during the washing, it is convenient because, for example, when the washing state reaches a prescribed state, the washing can be ended and the analysis can be started. Therefore, it is an object of the present invention to provide a capillary electrophoresis apparatus capable of efficiently performing a cleaning operation by making it possible to know the cleaning state during cleaning.

[0004]

According to the present invention, the surface condition of the inner surface of the capillary is measured during liquid feeding by measuring the flow voltage generated when a pressure difference is generated between both ends of the capillary to feed the liquid in the capillary. By knowing it and feeding it back to the cleaning operation, the analysis can always be performed in a stable state. Therefore, in the present invention, means for feeding the liquid into the capillary by the pressure difference between both ends of the capillary,
And a means for measuring a flow voltage generated between both ends of the capillary by feeding a liquid into the capillary under a state where a pressure difference is generated between both ends of the capillary.

[0005]

[Function] Flow velocity due to electroosmotic flow Ve.o (= Me.o ・ E)
Is represented as follows. Ve.o = εζE / 4πη where ζ is the zeta potential of the electric double layer, and ε and η are the dielectric constant and viscosity coefficient of the substance filling the electric double layer, respectively. From Ohm's law, V = IL / ak. Here, V is voltage, I is current, L is length, a is cross-sectional area, and k is specific conductivity. Therefore, Ve.o = (εζ / 4πη) (V / L) = (εζ / 4πηk) (I / a) (1)

On the other hand, a streaming potential (Stream) generated at both ends when a liquid is moved through a capillary by a phenomenon opposite to electroosmosis.
ing Potential) Vst is expressed as Vst = (εζ / 4πηk) P (2). Here, P is a pressure difference between both ends of the capillary. Therefore, if the pressure difference P between both ends of the capillary is constant, the coefficient (εζ / 4π) is changed by the fluctuation of the streaming potential Vst.
It is possible to know the fluctuation of ηk), and when P is changed, the fluctuation of the coefficient (εζ / 4πηk) can be known by measuring P.

On the other hand, in the equation (1), the cross-sectional area a is considered to be almost unchanged, the electric current I generated by electroosmosis is I = Vak / L, the voltage V during migration is known, L is unchanged, and Although the specific conductivity k in the multilayer is not known, it is considered that k is constant if the value of (εζ / 4πηk) is constant. Therefore, the surface state of the inner surface of the capillary that contributes to electroosmosis is measured by measuring the streaming potential Vst. I can know.

By measuring the streaming potential Vst during washing and terminating the washing when it reaches a steady value, the electroosmosis can be analyzed in a constant state. When the capillary is first washed with the washing liquid and then the flowing voltage is measured by replacing the liquid sending with the buffer liquid, the analysis can be started immediately when the flowing voltage reaches a steady value.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic configuration diagram showing the whole of one embodiment,
FIG. 2 is a cross-sectional view showing the liquid feeding section in detail. In FIG. 1, one turntable 7 holds a plurality of vials 9, and the vials 9 contain a sample, a buffer solution, a cleaning solution, and the like. The other turntable 8 also holds a plurality of vials 10, and the vial 10 contains a buffer solution or is empty. The turntables 7 and 8 are rotatably supported on the table 16 by respective rotating shafts. A pulley 13 is attached to the lower end of the rotary shaft of the turntable 7, and a pulley 14 attached to the rotary shaft of a stepping motor 15 for driving.
The belt 12 is hung between them and the turntable 7 is driven by the stepping motor 15 to rotate. Similarly, the other turntable 8 has a pulley 13a attached to the lower end of its rotary shaft, and a pulley 14a attached to the rotary shaft of a stepping motor 15a for driving.
The belt 12a is hung between the turntable 7 and
Is driven by the stepping motor 15a to rotate.

A female screw is provided on the table 16, and a ball screw 17 attached by a coupling 18 to a rotary shaft of a stepping motor 19 meshes with the female screw, and the rotation of the ball screw 17 causes the table 16 to move vertically. The two turntables 7 and 8 also move in the vertical direction along with the movement. A capillary 1 made of fused silica is held above the turntables 7 and 8. One end of the capillary 1 is fixedly held by the holding member 32 together with the electrode 2 arranged closely, and the other end of the capillary 1 is fixedly held by another holding member together with the electrode 3 arranged closely. A detector 4 is arranged on the other end side of the capillary 1. One end of the capillary 1 and the electrode 2 are arranged so as to be inserted into the vial 9 held by the turntable 7, and the other end of the capillary 1 and the electrode 3 are arranged in the vial 10 of the other turntable 8.
It is located at the position where it is inserted into.

In order to pressurize and feed the cleaning liquid or the buffer liquid into the capillary 1 from one end thereof, the vial 9 is inserted when the electrode 2 and one end of the capillary 1 are inserted into the vial 9.
As shown in FIG. 2, the holding member 32 is a cap of the vial 9 so that the inside can be hermetically sealed, and the sealing member 27 for sealing the inside of the vial 9 is provided, and the capillary 1 is kept airtight by the seal 28. The electrode 2 is also held in an airtight manner. A pipe 30 is connected through a joint 29 of a holding member 32 to pressurize the inside of the vial 9,
The pipe 30 is connected to a gas pressure source or an opening by a three-way solenoid valve 31.

Returning to FIG. 1, contacts 20 and 21 are attached to a rack 22 at one end of the capillary 1 in order to bring the electrode 2 into contact with the high voltage contact 20 or the flow voltage measuring contact 21. Reference numeral 22 meshes with a gear 23 attached to the rotating shaft of a motor 24. Capillary 1
The electrode 3 on the other end side is connected to the switching relay 6, and the relay 6 is connected to the high voltage power source 5 and the voltage measuring device 25 by switching. The anode of the high-voltage power supply 5 is connected to the high-voltage contact 20, the cathode is grounded, and is connected to the electrode 3 via the relay 6. The flow voltage measuring contact 21 is connected to the voltage measuring device 25, and the voltage measuring device 2
5 is connected to the electrode 3 via the relay 6. A controller 26 controls the rotation of the turntables 7 and 8 and the vertical movement of the table 16, and also controls the on / off operation of the high-voltage power supply 5 and the measurement operation of the voltage measuring device 25.

Next, the operation of this embodiment will be described.
By rotating the turntable 7 to select an arbitrary vial 9 and raising the table 16, the selected vial 9 is sealed by the seal 27 of the holding member 32,
One end of the capillary 1 and the electrode 2 are inserted into the vial 9. At this time, the other end of the capillary 1 and the electrode 3 are inserted into the vial 10 of the turntable 8. When the capillary 1 is washed, the vial 9 containing the washing liquid is selected. Electrode 2 with vial 9 sealed
The contact 21 for measuring the flowing voltage is brought into contact with the three-way solenoid valve 3
1 is switched to the gas pressure source side, and the cleaning liquid in the vial 9 is caused to flow inside the capillary 1 and discharged to the vial 10 side. At this time, the relay 6 is switched to the voltage measuring device 25 side, the voltage measuring device 25 measures the voltage between the electrodes 2 and 3, measures the flowing voltage, and sends the value to the controller 26. The washing operation is terminated when the streaming voltage reaches a steady state.

As another cleaning method, the cleaning is started with the cleaning liquid, the table 16 is temporarily lowered during the cleaning, and the turntable 7 is turned on.
Select the buffer solution with, raise the table 16 again, insert one end of the capillary 1 and the electrode 2 into the vial 9 and seal it, and insert the other end of the capillary 1 and the electrode 3 into the vial 10 to open the vial 9. The buffer solution is pressurized and the buffer solution is sent into the capillary 1, and the flow voltage between both ends of the capillary is measured.
When the flowing voltage reaches a steady state, the cleaning operation is terminated,
It is also possible to switch to the measurement operation immediately.
In the embodiment, pressure is applied to feed the liquid to the capillary,
On the contrary, the vial 9 on the side of the electrode 2 may be opened, and the vial 10 on the side of the electrode 3 may be hermetically closed and put in a depressurized state, so that liquid can be sent to the capillary.

[0015]

According to the present invention, the cleaning state of the inner surface of the capillary is known by detecting the flow voltage during the cleaning of the capillary. Therefore, conventionally, the cleaning state of the capillary cannot be known unless the sample is actually analyzed. What did not exist
According to the present invention, the washing state can be determined in the washing process, and the analysis can always be performed in the same state. When cleaning is performed using a plurality of liquids, it is difficult to determine whether or not the cleaning effect is sufficiently exhibited by each cleaning liquid in the related art, but the present invention enables such determination. Therefore, the cleaning process does not take an unnecessarily long time, and the cleaning can be performed in the shortest time according to the state inside the capillary.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an entire embodiment.

FIG. 2 is a cross-sectional view of a liquid delivery part in the example.

[Explanation of symbols] 1 capillary 2,3 electrode 4 detector 5 high voltage power supply 6 switching relay 7,8 turntable 9,10 vial 20 high voltage contact 21 streaming potential measurement contact 25 voltage measuring device 31 three-way solenoid valve

Claims (1)

[Claims] 1. A detector detects a substance electrophoresing in the capillary and a neutral substance moving by an electroosmosis method by a voltage applied to both ends of the capillary, and the elution time of each peak is measured from the detection signal. In a capillary electrophoresis apparatus, means for sending a liquid into a capillary by a pressure difference between both ends of the capillary, and a flow voltage generated between both ends of the capillary by sending a liquid into the capillary under a state where a pressure difference is generated between both ends of the capillary. A capillary electrophoresis apparatus comprising: