CN115335690A - Electrodes and Electrode Chips - Google Patents

Abstract

The present invention provides an electrode and an electrode chip capable of improving the measurement sensitivity and reproducibility of electrochemical measurement. The electrode chip (2) is provided with: a metal layer (41) formed on an insulating substrate (21); a carbon layer (42) formed on the metal layer (41); and an upper adhesive layer (44), It is formed between the upper surface of the metal layer (41) and the carbon layer (42). The upper adhesive layer (44) is formed of silicon. The sides of the metal layer (41) are covered by an insulating layer (25).

Description

Electrodes and Electrode Chips

technical field

The invention relates to an electrode and an electrode chip.

Background technique

The measurement using the principle of electrochemical measurement is used in many scenarios: high-sensitivity measurement of heavy metals in solution, glucose measurement using an enzyme electrode, measurement of pH (hydrogen ion concentration index) using an ion electrode, electrochemical detection of residual pesticides Representative food inspection (for example, refer to Patent Document 1) and the like. In particular, the measurement of heavy metals such as cadmium, mercury, arsenic, cobalt, copper, zinc, and lead is carried out before ingesting the amount of these heavy metals contained in water, soil, food, vegetables, rice, and drinking water into the body. Mastery is very important.

In electrochemical measurement, it is known that an electrode chip in which electrodes are formed on an insulating substrate can be used. In the electrode chip, the electrodes basically have a single-layer structure, and metal materials such as silver, platinum, gold, and aluminum or conductive materials such as carbon are used as electrode materials.

However, metal materials contain components that corrode due to redox reactions with moisture in the air or samples, and the measurement sensitivity and reproducibility may decrease. In addition, although carbon materials are not easily oxidized and reduced, their resistivity is higher than that of metal materials, and their sensitivity is poor when used as electrodes.

As a method of solving such problems, a method of laminating a carbon layer on a metal layer formed on an insulating substrate is known (for example, refer to Patent Documents 2-4).

However, conventional electrodes have problems in that hydrogen is generated on the surface of the metal layer due to water permeating the carbon layer during measurement, peeling between the metal layer and the carbon layer occurs, and damage to the carbon layer occurs, thereby reducing measurement sensitivity and reproducibility. .

prior art literature

patent documents

Patent Document 1: Japanese Patent Application Laid-Open No. 11-248668

Patent Document 2: Japanese Patent No. 5120453

Patent Document 3: Japanese Patent Laid-Open No. 2013-190212

Patent Document 4: Japanese Patent Laid-Open No. 2014-153280

Contents of the invention

The problem to be solved by the invention

The present invention was made to improve the above-mentioned present situation, and an object of the present invention is to provide an electrode and an electrode chip capable of improving the measurement sensitivity and reproducibility of electrochemical measurement for measuring trace components in a liquid sample.

solutions to problems

The electrode of the present invention includes: a metal layer formed on an insulating substrate; a carbon layer formed on the metal layer; and an upper adhesive layer formed on the upper surface of the metal layer and the carbon layer. In between, the upper adhesive layer is formed of silicon, and the side surfaces of the metal layer are covered by an insulating layer.

According to the electrode of the present invention, since the electrode has a metal layer, the electrical resistance is reduced, so that the measurement sensitivity can be improved. In addition, by covering the upper surface of the metal layer with a carbon layer and covering the side surfaces of the metal layer with an insulating layer, oxidation and reduction of the metal layer can be prevented, and measurement sensitivity and reproducibility can be improved. Moreover, by providing an upper adhesive layer made of silicon between the upper surface of the metal layer and the carbon layer, the adhesion between the metal layer and the carbon layer is improved, and since silicon has a higher resistivity than metal, it is possible to suppress the measurement. The generation of hydrogen on the upper surface of the metal layer and prevent the peeling of the metal layer and the carbon layer, thereby improving the measurement sensitivity and reproducibility. In addition, since the side surface of the metal layer is covered with the insulating layer, moisture does not reach the side surface, and generation of hydrogen on the side surface of the metal layer can be prevented.

In the electrode of the present invention, a lower adhesive layer formed between the substrate and the metal layer may be provided.

According to such a configuration, it is possible to prevent a decrease in the adhesion between the substrate and the metal layer during measurement, and to improve measurement sensitivity and reproducibility.

Preferably, the lower adhesive layer is formed of, for example, silicon, chromium, titanium, tungsten, or a surface treatment layer obtained by subjecting the surface of the substrate to a surface treatment that improves the adhesion between the substrate and the metal layer. However, the lower adhesive layer may also be formed of metals other than the above.

The electrode chip of the present invention includes a working electrode (working electrode) and a reference electrode (reference electrode) composed of the electrode of the present invention.

According to the electrode chip of the present invention, it can be suitably used for electrochemical measurement of a two-electrode system using a working electrode and a reference electrode. In addition, both the working electrode and the reference electrode are composed of the electrode of the present invention having a metal layer, a carbon layer, and an adhesive layer. Therefore, for both the working electrode and the reference electrode, since the resistance can be reduced, the metal can be prevented. The redox of the layer and the peeling of the carbon layer can be prevented, so the measurement sensitivity and reproducibility can be improved.

In the electrode chip of the present invention, a counter electrode composed of the electrode of the present invention may be further provided.

According to such a configuration, it can be applied to electrochemical measurement of a three-electrode system using a working electrode, a reference electrode, and a counter electrode. In addition, with respect to the working electrode, reference electrode, and counter electrode, since resistance can be reduced, oxidation and reduction of the metal layer can be prevented, and peeling of the carbon layer can be prevented, so that measurement sensitivity and reproducibility can be improved.

Invention effect

The present invention can provide an electrode and an electrode chip capable of improving measurement sensitivity and reproducibility of electrochemical measurement.

Description of drawings

FIG. 1 is a schematic configuration diagram showing an example of an electrochemical measurement device.

FIG. 2 is a schematic plan view showing an embodiment of an electrode chip.

FIG. 3 is a schematic cross-sectional view corresponding to the position AA of FIG. 2 .

Fig. 4 is a schematic cross-sectional view showing another embodiment of the electrode chip.

Detailed ways

Embodiments of the electrode and the electrode chip of the present invention will be described based on the drawings. FIG. 1 is a schematic configuration diagram showing the embodiment. Fig. 2 is a plan view showing an embodiment of an electrode chip.

As shown in FIG. 1 , an electrochemical measurement device 1 includes an electrode chip 2, a potentiostat 3 connected to the electrode chip 2, an operation unit 4 connected to the potentiostat 3, a display unit 5, a power supply unit 6, and an external output unit 7. . In this embodiment, the electrode chip 2 is a disposable electrode chip.

As shown in FIG. 2 , the electrode chip 2 includes a flat insulating substrate 21 , and a working electrode 22 , a counter electrode 23 , and a reference electrode 24 are provided on the substrate 21 insulated from each other. The substrate 21 has a substantially rectangular shape in plan view. The working electrode 22 , the counter electrode 23 , and the reference electrode 24 are provided so as to extend from the vicinity of one end in the longitudinal direction of the substrate 21 to the vicinity of the other end.

An insulating layer 25 is formed on the substrate 21 to insulate the working electrode 22 , the counter electrode 23 , and the reference electrode 24 from each other. The insulating layer 25 is embedded between the electrodes 22 , 23 , and 24 , and is provided so as to surround the contours of the electrodes 22 , 23 , and 24 so as to cover the side surfaces of the electrodes 22 , 23 , and 24 .

In the electrode chip 2 , the liquid sample 10 containing the substance to be measured is in contact with one end side of the working electrode 22 , the counter electrode 23 , and the reference electrode 24 . The other ends of the working electrode 22 , the counter electrode 23 , and the reference electrode 24 of the electrode chip 2 are electrically connected to the potentiostat 3 via the connector 8 and the cable 9 (not shown in FIG. 1 ). The electrode chip 2 is detachably attached to the connector 8 .

At least one surface of the substrate 21 of the electrode chip 2 is formed of a flat insulating material. The material of the substrate 21 is not particularly limited, and examples thereof include polyimide (PI: polyimide), glass, polyethylene terephthalate (PET: polyethyleneterephthalate), polymethylmethacrylate resin (PMMA: polymethylmethacrylate) , polycarbonate (PC: polycarbonate), polypropylene (PP: polypropylene), polyethylene (PE: polyethylene), polystyrene (PS: polystyrene), polyvinyl chloride (PVC: polyvinylchloride), polyoxymethylene (POM: polyoxymethylene ), ABS resin (ABS (acrylonitrile-butadiene-styrene): acrylonitrile-butadiene-styrene), etc. However, the material of the substrate 21 is not limited to these, and may be ceramics, quartz, or the like. In addition, the shape, thickness, and size of the substrate 21 are not particularly limited.

As shown in Fig. 2 and Fig. 3, in electrode chip 2, working electrode 22, counter electrode 23 and reference electrode 24 possess respectively: metal layer 41, is formed on substrate 21; Carbon layer 42, covers metal layer 41 and A lower adhesive layer 43 is formed between the substrate 21 and the metal layer 41 ; and an upper adhesive layer 44 is formed between the upper surface of the metal layer 41 and the carbon layer 42 . A silver silver chloride layer 45 is formed on the upper surface of the carbon layer 42 on one end side of the reference electrode 24 .

The lower adhesive layer 43 is a thin film for preventing peeling of the substrate 21 and the metal layer 41 , and is formed of silicon, for example. The material of the lower adhesive layer 43 may be any material as long as it has good adhesion between the substrate 21 and the metal layer 41 , and other than silicon, for example, chromium, titanium, and tungsten may be used.

In addition, the lower adhesive layer 43 may be formed of a surface treatment layer formed by subjecting the surface of the substrate 21 to a surface treatment to improve the adhesion between the substrate 21 and the metal layer 41 . Such surface treatment includes, for example, plasma treatment, corona treatment, flame treatment, etching treatment, steam treatment, ion beam treatment, and the like.

Metal layer 41 is made of a material having a lower resistivity than carbon layer 42 , and is formed on lower adhesive layer 43 . The metal layer 41 is a layer for reducing the resistance between one end and the other end of each of the working electrode 22 , the counter electrode 23 , and the reference electrode 24 . As the material of the metal layer 41 , for example, silver, ruthenium, tantalum, titanium, copper, aluminum, platinum, niobium, zirconium, alloys of these elements, alloys of these elements and carbon, or the like can be used.

The upper adhesive layer 44 is formed on the upper surface of the metal layer 41 , is a thin film that prevents the upper surface of the metal layer 41 from being peeled off from the carbon layer 42 , and is made of silicon.

The carbon layer 42 is formed on the metal layer 41 via the upper adhesive layer 44 . The carbon layer 42 is formed of, for example, amorphous carbon or diamond-like carbon (DLC: diamond-like carbon).

Carbon is suitable for use in the carbon layer 42 that protects the metal layer 41 because it has the following characteristics. (1) It has excellent stability even in a vacuum of 3000°C (in the air of 500°C); (2) It is not easily corroded by chemicals; (3) It is impermeable to gases and solutions; (4) It has excellent hardness , strength; (5) has excellent electrical conductivity; (6) has resistance to wetting of metal salts, etc.; (7) has good blood and tissue compatibility; (8) has isotropic physical and chemical properties .

As a method of manufacturing lower adhesive layer 43 , metal layer 41 , upper adhesive layer 44 , and carbon layer 42 , vapor deposition is preferable from the viewpoint of being able to control the shape and film thickness of each layer with high precision. Here, as the vapor deposition method, so-called physical vapor deposition (PVD: physical vapor deposition) such as vacuum vapor deposition, ion plating, and sputtering, and so-called chemical vapor deposition (CVD: chemical vapor deposition) can be used. . However, the manufacturing method of each layer is not limited to the vapor deposition method, but printing methods such as screen printing method and inkjet printing method may also be used.

As shown in FIGS. 2 and 3 , the insulating layer 25 is formed in an outline surrounding the lower adhesive layer 43 , the metal layer 41 , and the upper adhesive layer 44 in plan view. The side surfaces of the metal layer 41 are covered with the insulating layer 25 . In this embodiment, the side surfaces of the lower adhesive layer 43 , the upper adhesive layer 44 , and the carbon layer 42 are also covered with the insulating layer 25 . The lower surface of the insulating layer 25 is in contact with the substrate 21 . The lower adhesive layer 43 , the metal layer 41 and the upper adhesive layer 44 are isolated from the surrounding atmosphere due to being surrounded by the substrate 21 and the insulating layer 25 .

The material of insulating layer 25 is not particularly limited, and examples thereof include silicon oxide film (SiO ₂ ), silicon nitride film (Si ₃ N ₄ ), aluminum oxide film (Al ₂ O ₃ ), and the like. However, the insulating layer 25 is not limited to layers made of these materials, as long as it can isolate the side surfaces of the electrodes 22, 23, 24 (at least the side surfaces of the metal layer 41) from the surrounding atmosphere and prevent moisture from passing through.

It should be noted that the height position (thickness) of the upper surface of the insulating layer 25 may be such that the insulating layer 25 can cover at least the side surfaces of the metal layer 41 . Here, in order to increase the contact area between the insulating layer 25 and the carbon layer 42 , it is preferable that the height position of the upper surface of the insulating layer 25 is approximately the same as the height position of the upper surface of the carbon layer 42 . Thereby, infiltration of moisture into the metal layer 41 from between the insulating layer 25 and the carbon layer 42 can be reliably prevented.

In this embodiment, the electrodes 22, 23, and 24 include: a metal layer 41 formed on the insulating substrate 21; a carbon layer 42 formed on the substrate 21 so as to cover the metal layer 41; and a lower adhesive layer. 43 , formed between the substrate 21 and the metal layer 41 . Since the electrodes 22, 23, and 24 have the metal layer 41, the electrical resistance is reduced, and the measurement sensitivity can be improved. In addition, by covering the upper surface of the metal layer 41 with the carbon layer 42 and covering the side surfaces of the metal layer 41 with the insulating layer 25, oxidation and reduction of the metal layer 41 can be prevented, and measurement sensitivity and reproducibility can be improved. Furthermore, by providing the upper adhesive layer 44 made of silicon between the upper surface of the metal layer 41 and the carbon layer 42, the adhesion between the metal layer 41 and the carbon layer 42 is improved, and since the resistivity of silicon is higher than that of metal, High enough to suppress the generation of hydrogen on the upper surface of the metal layer 41 during measurement. In addition, since the side surface of the metal layer 41 is covered with the insulating layer 25 , moisture does not reach the side surface, and generation of hydrogen on the side surface of the metal layer 41 can be prevented. Thereby, peeling of the substrate 21 and the metal layer 41 is prevented, and measurement sensitivity and reproducibility can be improved.

In addition, since the electrodes 22, 23, and 24 are provided with the lower adhesive layer 43 formed between the substrate 21 and the metal layer 41, it is possible to prevent the decrease in the adhesion between the substrate 21 and the metal layer 41 during measurement, and to improve the measurement performance. Sensitivity and reproducibility.

In addition, metal layer 41, carbon layer 42, and adhesive layers 43, 44 are layers formed by vapor deposition, and metal layer 41, carbon layer 42, and adhesive layers 43, 44 are formed in the same shape in plan view. By forming each layer 41, 42, 43, 44 by vapor deposition, the shape and film thickness of each layer 41, 42, 43, 44 can be controlled with high precision, and the overall electrode 22, 23, 24 can be improved for each electrode 22, 23, 24. resistance stability.

In addition, the lower adhesive layer 43 is formed of silicon. Since silicon has good adhesion to glass and metal, it can enhance the adhesion between the metal layer 41 and the substrate 21 . In addition, the upper adhesive layer 44 is also formed of silicon. Since silicon has good adhesion to metal and carbon, the adhesion between metal layer 41 and carbon layer 42 can be enhanced.

The electrode chip 2 includes a working electrode 22 , a reference electrode 24 , and a counter electrode 23 , so it can be applied to electrochemical measurements of a three-electrode system. In addition, the working electrode 22, the reference electrode 24, and the counter electrode 23 can reduce resistance, prevent oxidation and reduction of the metal layer 41, and prevent peeling of the metal layer 41, so that measurement sensitivity and reproducibility can be improved.

It should be noted that the electrode chip according to the present invention can be applied to electrochemical measurement of a two-electrode system using a working electrode and a reference electrode. In addition, both the working electrode and the reference electrode are composed of the electrode of the present invention having a metal layer, a carbon layer, and an adhesive layer. Therefore, for both the working electrode and the reference electrode, since the resistance can be reduced, the metal can be prevented. The redox of the metal layer can prevent the peeling of the metal layer, so the measurement sensitivity and reproducibility can be improved.

As shown in FIG. 1 , the potentiostat 3 is configured to control the potential of the working electrode 22 of the electrode chip 2 with respect to the reference electrode 24 in a constant manner, and can measure the voltage flowing between the working electrode 22 and the counter electrode 23. current. As a schematic configuration, the potentiostat 3 includes an arithmetic control unit 31 , a voltage application unit 32 , and a current detection unit 33 .

The calculation control unit 31 performs a predetermined calculation process using the measured value obtained by electrochemical measurement, and transmits a signal required by the voltage applying unit 32 or makes the display unit 5Display information such as measurement results. The arithmetic control unit 31 is realized, for example, by a microcomputer executing a predetermined program.

The voltage application unit 32 is configured to apply a voltage of a desired waveform between the working electrode 22 and the counter electrode 23 of the counter electrode chip 2 when receiving the measurement start signal from the calculation control unit 31, so that the working electrode 22 and the counter electrode 23 are connected to each other. Control is performed so that the potential between the specific electrodes 24 becomes a desired potential.

The current detection unit 33 is configured to detect the magnitude of the current flowing between the working electrode 22 and the counter electrode 23 of the electrode chip 2 . A signal related to the magnitude of the current detected by the current detection unit 33 is taken into the arithmetic control unit 31 .

The arithmetic control unit 31 is configured to calculate the concentration of a specific component in the sample solution based on the signal received from the current detection unit 33 using, for example, a calibration curve prepared in advance, and display the measurement result on the display unit 5 .

In the electrochemical measurement device 1 , the operation unit 4 is an input device for the user to perform operations such as turning on/off a power supply, starting a measurement, and changing information displayed on the display unit 5 . The display unit 5 is realized by, for example, a liquid crystal display. It should be noted that the display unit 5 may be configured with a touch panel, and the display unit 5 may also function as the operation unit 4 . The power supply unit 6 can be realized by, for example, a dry cell, a storage battery, or the like. Necessary electric power is supplied to the potentiostat 3 and the display unit 5 through the power supply unit 6 .

In addition, an external output unit 7 may be connected to the potentiostat 3 so that information can be output to external devices such as a personal computer through a wired communication unit such as a USB (universal serial bus) terminal or a wireless communication unit. . In this case, the arithmetic control unit 31 is configured to output measurement data and the like to an external device through the external output unit 7 .

It should be noted that the operation unit 4 , the display unit 5 , the power supply unit 6 , and the external output unit 7 may be realized by, for example, mobile computers such as notebook computers and tablet computers. Furthermore, if a small potentiostat (for example, a small potentiostat "miniSTAT100" (manufactured by BioDevice Technology)) is used as the potentiostat 3, the electrochemical measuring device 1 can be configured to be portable. This enables on-site measurement of a liquid sample using the electrochemical measurement device 1 .

As shown in FIG. 2 , the electrochemical measurement using the electrochemical measurement device 1 is performed in a state where the liquid sample 10 is dripped on the electrode chip 2 . With respect to the electrode chip 2 , the liquid sample 10 is dropped onto the substrate 21 so as to be in contact with the working electrode 22 , the counter electrode 23 and the reference electrode 24 . In addition, the measurement may be performed in the state which immersed the one end side of the working electrode 22, the counter electrode 23, and the reference electrode 24 in the liquid sample.

Next, a fabrication example of the electrode chip 2 will be described. On a glass substrate with a thickness of about 2500 nm (2.5 μm) as the substrate 21, a silicon layer with a thickness of about 20 nm is formed as the lower part by sputtering using a metal mask having an opening pattern corresponding to the region where the lower adhesive layer is formed. Adhesive layer 43 . It should be noted that the film thickness of the lower adhesive layer 43 formed of silicon is not particularly limited.

Using a metal mask having the same opening pattern as the opening pattern corresponding to the lower adhesive layer forming region of the metal mask, a silver layer with a thickness of about 150 nm is formed as a metal layer on the lower adhesive layer 43 by sputtering. Layer 41.

Then, using a metal mask having the same opening pattern as that corresponding to the lower adhesive layer forming region, a silicon layer with a thickness of about 20 nm is formed as upper adhesive layer 44 on metal layer 41 by sputtering. It should be noted that the film thickness of the upper adhesive layer 44 formed of silicon is not particularly limited.

Next, a carbon layer 42 having a thickness of about 1000 nm is formed on the upper adhesive layer 44 by sputtering using a metal mask having the same opening pattern as that corresponding to the lower adhesive layer forming region. In this way, the working electrode 22 , the counter electrode 23 , and the reference electrode 24 each having the lower adhesive layer 43 , the metal layer 41 , the upper adhesive layer 44 , and the carbon layer 42 are formed.

Here, after the substrate 21 is carried into the chamber of the sputtering apparatus, the lower adhesive layer 43, the metal layer 41, the upper adhesive layer 44, and the carbon layer 42 are deposited using the same metal mask without being removed from the chamber. A film is formed on the substrate 21 . Accordingly, the time required for film formation of the lower adhesive layer 43 , the metal layer 41 , the upper adhesive layer 44 , and the carbon layer 42 can be shortened, and adhesion of foreign matter between the layers can be prevented. In addition, the metal layer 41, the carbon layer 42, and the adhesive layers 43 and 44 are formed in the same shape when viewed from above.

The line width (dimension in the width direction perpendicular to the longitudinal direction) of the electrodes 22, 23, 24 is about 1.0 mm. In addition, the distance between the electrodes 22, 23, and 24 is about 0.5 mm.

By sputtering, a metal mask having an opening pattern opening around the region where the lower adhesive layer is formed is used to cover the lower adhesive layer 43, the metal layer 41, the upper adhesive layer 44, and the side surfaces of the carbon layer 42 (electrode 22, 23, 24), an insulating layer 25 with a thickness of about 1200 nm is formed on the substrate 21. The insulating layer 25 is formed so as to surround the electrodes 22 , 23 , and 24 and is embedded between the electrodes 22 , 23 , and 24 .

In this way, the lower adhesive layer 43, the metal layer 41, the upper adhesive layer 44, the carbon layer 42, and the insulating layer 25 are formed by vapor deposition (here, sputtering) using a metal mask having an opening pattern, This eliminates the need for patterning by etching or lift-off after film formation of each layer, thereby reducing manufacturing costs.

On the upper surface of the carbon layer 42 on the one end side of the reference electrode 24, a silver layer with a thickness of about 100 nm was formed by a film-forming method and subjected to chlorination treatment to form a silver-silver chloride layer 45 . In this way, the electrode chip 2 is manufactured. It should be noted that the silver-silver chloride layer 45 may be formed after the insulating layer 25 is formed, or the silver-silver chloride layer 45 may be formed before the insulating layer 25 is formed.

The film thickness of the metal layer 41 is not particularly limited, but is preferably not less than 50 nm and not more than 1000 nm. In addition, when the film thickness of the metal layer 41 is thinner than 50 nm, the electrodes 22, 23, 24 become high resistance, and measurement sensitivity falls. In addition, when the film thickness of the metal layer 41 is thicker than 1000 nm, when the metal layer 41 is formed into a film by a vapor deposition method (such as a sputtering method), the time required for the film formation of the metal layer 41 becomes longer, and the production efficiency is significantly reduced. reduce.

It should be noted that, after forming a plurality of electrode chips 2 in a region where a plurality of electrode chips 2 are provided on one substrate 21 at the same time, each electrode chip 2 is singulated, thereby reducing the manufacturing cost.

In the electrode chip 2, as shown in FIG. 4 , a surface treatment layer 46 may be formed on the surface of the substrate 21 for surface treatment to improve adhesion as a lower adhesive layer. A metal layer 41 and an insulating layer 25 are formed thereon. Thus, the adhesion between the substrate 21 and the metal layer 41 and the insulating layer 25 can be improved, the intrusion of moisture from between the substrate 21 and the insulating layer 25 can be reliably prevented, and the occurrence of moisture on the side of the metal layer 41 during measurement can be more reliably prevented. The generation of hydrogen and the peeling off of the insulating layer 25.

The present invention is not limited to the aforementioned embodiments, and can be embodied in various forms. For example, the electrode chip may have a configuration that does not include the counter electrode 23 but includes the working electrode 22 and the reference electrode 24 as electrodes, and may be applicable to electrochemical measurement using a two-electrode method.

In addition, the electrode chip of the present invention can also be applied to linear sweep voltammetry (LSV: linear sweepvoltammetry), chronoamperometry (CA: chronoamperometry), cyclic voltammetry (CV: cyclicvoltammetry), short wave voltammetry (SWV) etc. method, not limited to differential pulse voltammetry (DPV: differentialpulse voltammetry).

Explanation of reference signs

1: Electrochemical determination device;

2: electrode chip;

3: potentiostat;

4: Operation Department;

5: display unit;

6: Power supply unit;

7: External output unit;

8: Connector;

9: cable;

10: liquid sample;

21: Substrate;

22: working electrode;

23: counter electrode;

24: reference electrode;

25: insulating layer;

31: Operation control department;

32: voltage applying part;

33: current detection unit;

41: metal layer;

42: carbon layer;

43: lower bonding layer;

44: upper bonding layer;

45: silver silver chloride layer;

46: surface treatment layer.

Claims (5)

1. An electrode comprising: a metal layer formed on an insulating substrate; a carbon layer formed over the metal layer; and an upper adhesive layer formed between the upper surface of the metal layer and the carbon layer, the upper adhesive layer is formed of silicon, The sides of the metal layer are covered by an insulating layer. 2. The electrode according to claim 1, comprising: The lower bonding layer is formed between the substrate and the metal layer. 3. The electrode according to claim 2, wherein, The lower adhesive layer is formed of silicon, chromium, titanium, tungsten, or a surface treatment layer that is subjected to a surface treatment on the surface of the substrate to improve the adhesion between the substrate and the metal layer. way formed. 4. An electrode chip, which has: The working electrode and the reference electrode are made of the electrodes according to any one of claims 1 to 3. 5. electrode chip according to claim 4, it also has: The counter electrode is made of the electrode according to any one of claims 1 to 3.

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