JP2833080B2 - Electrophoresis analyzer - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a capillary type isotachophoresis analyzer, and more particularly, to an electrophoresis analyzer for improving productivity when forming electrodes.

<Conventional technology> Isokinetic electrophoresis analysis is a type of separation analysis in which an electrolyte solution contains ions of the same sign that have higher mobilities than the analysis target ion that is the leading solution, and moves less than the analysis target ion that is the terminal solution. Electrolyte containing ions of the same sign is contacted at the interface in the electrophoresis capillary, and a sample solution (hereinafter, simply referred to as sample) is injected into the interface, and a constant voltage is applied to both ends of the capillary to remove the ions to be analyzed. Separated in order of their mobility,
This is an analysis method that performs qualitative and quantitative measurements by measuring the conductivity and potential gradient of separated ions.

FIG. 6 shows a conventional example of such a device, in which 1 is a terminal electrolyte tank and 2 is a leading electrolyte tank. In these electrolyte layers, electrodes 4 and 4 connected to a high-voltage power supply 3 are provided. 5 are dipped. 6 is an electrophoresis capillary, both ends of which are electrolyte layers
Connected to 1,2. Reference numeral 7 denotes a detector provided in the middle of the electrophoresis capillary, and reference numerals 8 and 9 denote stop valves for controlling the amount of liquid to the electrolytic solution tank. Reference numeral 10 denotes a sample injection valve, which is opened and closed, and a sample is injected by the micro syringe 12. The electrophoresis capillary and the detector are arranged in a thermostat 11.

<Problem to be Solved by the Invention> In the above conventional example, the detector 7 is configured as shown in a sectional view in FIG. 7 (a). 7 (b) and 7 (c) are enlarged views of the electrode portion, (b) is for conductivity measurement in which the electrodes are arranged in contact with each other, and (c) is a potential gradient in which the opposing electrodes are displaced by about 50 μm. For measurement. In these figures, reference numeral 20 denotes a Pyrex glass tube having an outer diameter of about 6 mm, and reference numeral 21 denotes a Teflon cap having an outer diameter of about 10 mm formed so as to cover one end of the glass. In the Pyrex glass tube 20, platinum electrodes 23 and 23 'are buried opposite to the tube wall of the electrophoresis capillary 22 to measure the conductivity and potential gradient of the sample, and sealed with an epoxy resin 24 or the like. . Reference numerals 25 and 25 'denote lead wires connected to one end of the platinum electrode, and 27 denotes a Teflon tube for protecting the electrophoresis capillary.

By the way, in the configuration of the above detector, the outer diameter of the electrophoresis capillary is about 320 μm and the inner diameter is about 50 μm. When a platinum electrode is embedded in such a capillary, a through hole facing the capillary and a certain displacement are required. The through-hole is to be provided with a hole. However, as described above, this hole is very small and the glass tube is hard, so that the hole is conventionally formed using a gas laser.

However, when a hole is formed by a gas laser, it is extremely difficult to precisely control the alignment and the intensity of the laser beam, and there are problems in terms of production and cost.

The present invention has been made in order to solve the above-mentioned problems of the prior art. In the present invention, a detection electrode is formed on a silicon substrate by using a thin film technique so as to face each other, and a groove is formed by etching so as to pass through the center of the facing electrode. An object of the present invention is to realize a low-cost electrophoresis apparatus which is easy to manufacture by forming.

<Means for Solving the Problems> The configuration of the present invention for solving the above-mentioned problems of the prior art is as follows.
The terminal electrolyte and the leading electrolyte are introduced into the electrophoresis capillary from the terminal electrolyte tank and the leading electrolyte tank, respectively, and the sample solution is injected at the boundary between these electrolytes. In an electrophoresis analyzer that analyzes the components of the sample solution by detecting the electrical conductivity and potential gradient of the ions with a detection electrode, a groove formed on the surface by photolithography and etching techniques is used. A first substrate, a pair of detection electrodes made of a thin film provided in the middle of the groove, and a second substrate having a through hole at a position corresponding to the detection electrode provided on the first substrate; 1, second
The substrate is bonded to form a migration capillary by the groove, and a signal from the electrode is taken out through the through hole.

<Operation> The detection electrodes are formed facing each other by using the thin film technology, and the grooves are formed by etching so as to pass through the center of the facing electrodes. Therefore, mass production can be performed at low cost using a semiconductor process.

Hereinafter, the present invention will be described with reference to the drawings. FIG. 1 is an overall configuration diagram showing an embodiment of the present invention. In FIG. 1, 10
The first has a spiral groove (electrophoresis capillary) 12 formed on the surface.
Silicon substrate. Reference numeral 13 denotes a second silicon substrate on which through holes 15a to 15d (15b and 15c are omitted because a part is shown in cross section). The first and second silicon substrates have a thickness of about 0.5 mm and an area of about 100 mm ² . Reference numerals 18a and 18b denote pipes. One end of the pipe 18a on the suction side is inserted into the terminal electrolyte tank 1, and the other end communicates with one end of the groove 12 through a through hole (position indicated by 15c).

One end of the pipe 18b on the discharge side is a leading electrolyte tank 2
And the other end thereof communicates with the other end of the groove 12 through the through hole 15d. Reference numeral 21 denotes a high-voltage power supply, in which the negative electrode 4 is inserted into the terminal electrolyte tank 1 and the positive electrode 5 is inserted into the leading electrolyte tank 2. 22 is a detection electrode formed on both sides in the middle of the groove, 2
3 is an injector for injecting a sample.

In the above configuration, when a voltage is applied from the high voltage power supply 21, ions in the sample injected from the injector 23 to the interface of the electrolyte are separated in the order of their mobilities while moving through the narrow tube 12 from the terminal liquid tank 1 side to the leading liquid tank 2 side. Then, the conductivity and potential gradient corresponding to the components of the sample can be measured by the detection electrode 22 and a known signal detection circuit (not shown) connected thereto.

FIG. 2 shows the positional relationship between the groove (small tube), the electrode, and the through holes (electrode extraction holes) 15a and 15b, and is an enlarged perspective view in the case where the conductivity is measured. In the figure, the reference numerals are the same as those in FIG.
μm, and are arranged to face each other via the groove 12 (when measuring the potential difference, the facing electrodes are shifted by about 50 μm). The portion B serves as a connection terminal and is formed at a position exposed to the through holes 15a and 15b formed in the second substrate 13.

3 (a) to 3 (d) show schematic steps of forming the electrodes and grooves shown in FIG. 2 on a silicon substrate. A description will be given according to the steps.

Step (a) An oxide film 30, a nitride film 31, a lift-off layer 32, and a resist layer 33 are sequentially laminated on the first silicon substrate 10, and the resist layer is patterned into the shape of a detection electrode to form a lift-off layer 32.
To expose. (See FIG. A) Step (b) The lift-off layer 32 at the portion exposed by patterning is removed, and Cr and Pt as detection electrodes are formed on the exposed nitride film 31.
Is formed by sputtering or vapor deposition. (Figure b
Step (c) Lift-off is performed to remove other layers except the nitride film 31 and the detection electrode 35. (See FIG. C) Step (d) The nitride film 31 is patterned into a groove shape, and isotropically etched using a nitric hydrofluoric acid solution.

FIGS. 4 (a) and 4 (b) show a schematic process of forming a through-hole in the second silicon substrate.

Step (a) After forming an oxide film on the silicon substrate 13, a resist film is formed, a portion where a through hole is to be formed is patterned, and the exposed oxide film is removed. Step (b) Using the remaining oxide film as a mask, anisotropic etching is performed using a hydrazine solution to form through holes 15. (See FIG. 5 (b).) FIG. 5 shows a state in which the first and second silicon substrates produced according to FIGS. 3 and 4 are bonded together to form a migration capillary. After a thermal oxide film is sufficiently formed on the two substrates, a polyimide resin is applied on the surface and fixed by heating.

In this embodiment, the substrate is described as silicon, but the substrate is not limited to silicon, but may be glass, for example, or a combination thereof. Further, the adhesion between the substrates is not limited to the polyimide resin.

<Effects of the Invention> According to the present invention, as specifically described above with the embodiment, a first substrate having a groove formed on the surface by using photolithography and etching techniques, and a first substrate provided in the middle of the groove A pair of detection electrodes made of a thin film,
A second substrate having a through-hole at a position corresponding to a detection electrode provided on the substrate; the first and second substrates are attached to each other to form a migration capillary by the groove; and the detection is performed through the through-hole. Since it is configured to take out signals from the electrodes, it is possible to mass-produce grooves and thin films at a low cost by using a semiconductor process, thereby dramatically improving productivity.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing the configuration of an embodiment of the electrophoresis analyzer of the present invention, FIG. 2 is a perspective view showing an enlarged electrode portion, and FIGS. FIG. 6 is a diagram schematically showing the process, FIG. 6 is an overall configuration diagram of a conventional device, and FIG. 7 is an enlarged view of a detector of the conventional device. 1 ... Terminal electrolyte tank, 2 ... Reading electrolyte tank, 3 ... High voltage power supply, 10,13 ... Silicon substrate, 12 ... Groove (migrating capillary), 15 ... Through hole, 22a, 22b ... ... detection electrodes, 23 ...
… Injector.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-51-26594 (JP, A) JP-A-2-245655 (JP, A) JP-A-3-131750 (JP, A) 161886 (JP, U) (58) Field surveyed (Int. Cl. ⁶ , DB name) G01N 27/447

Claims (1)

(57) [Claims] 1. A terminal electrolytic solution and a leading electrolytic solution are introduced into a migration capillary from a terminal electrolytic solution tank and a leading electrolytic solution side, respectively. A sample solution is injected into a boundary between these electrolytic solutions, and ions in the sample are electrophoresed. Electrophoretic separation is performed according to the difference in speed, and the electroconductivity and potential gradient of the ions are detected by a detection electrode to analyze the components of the sample solution. The electrophoresis analyzer is formed on the surface using photolithography and etching techniques. A first substrate having a groove formed therein, a pair of detection electrodes made of a thin film provided in the middle of the groove, and a second substrate having a through hole at a position corresponding to the detection electrode provided on the first substrate. The first and second substrates are bonded to each other to form an electrophoretic thin tube by the groove, and to extract a signal from the detection electrode through the through hole. Electrophoresis analysis apparatus characterized by the Uni configuration.