Electrode and electrochemical measurement system

Abstract

An electrode (1) is provided with a base film (2) and a conductive carbon layer (4) in this order toward one side in the thickness direction. The water contact angle of one surface of the conductive carbon layer (4) in the thickness direction is 80 degrees or less.

Description

Technical Field

[0001] The present invention relates to an electrode and an electrochemical measurement system. Background Art

[0002] Conventionally, a carbon electrode including a substrate and a conductive carbon layer in this order in the thickness direction is known (for example, see Patent Document 1 listed below).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2021-056205 Summary of the invention

[0006] Problems to be solved by the invention

[0007] Electrodes are required to have excellent sensitivity to a measurement object, and the electrodes described in Patent Document 1 may not fully meet the above requirement.

[0008] The present invention provides an electrode and an electrochemical measurement system having excellent sensitivity to a measurement object.

[0009] Means for solving problems

[0010] The present invention [1] includes an electrode, which includes a substrate film and a conductive carbon layer in this order on one side in the thickness direction, and a water contact angle of one surface of the conductive carbon layer in the thickness direction is 80 degrees or less.

[0011] The present invention [2] includes the electrode described in [1], which further comprises a metal base layer arranged between the aforementioned substrate film and the aforementioned conductive carbon layer, and the aforementioned metal base layer is in contact with one surface of the aforementioned substrate film in the thickness direction and the other surface of the aforementioned conductive carbon layer in the thickness direction.

[0012] The present invention [3] comprises the electrode described in [1] or [2], wherein the electrode is an electrode for electrochemical measurement.

[0013] The present invention [4] includes an electrochemical measurement system comprising the electrode according to any one of [1] to [3].

[0014] Effects of the Invention

[0015] According to the present invention, the water contact angle of one surface of the conductive carbon layer in the thickness direction is 80 degrees or less. Therefore, the electrode and the electrochemical measurement system including the electrode have excellent sensitivity to the measurement object. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] [ Figure 1 ] is a cross-sectional view of one embodiment of the electrode of the present invention.

[0017] [ Figure 2 ] is a schematic diagram of one embodiment of the electrochemical measurement system of the present invention. DETAILED DESCRIPTION

[0018] 1. Electrodes

[0019] Reference Figure 1 One embodiment of the electrode of the present invention will be described.

[0020] The electrode 1 has a thickness. The electrode 1 extends in the surface direction. The surface direction is orthogonal to the thickness direction. The electrode 1 has a film shape. The thickness of the electrode 1 is, for example, 2 μm or more, preferably 10 μm or more, and, for example, 1000 μm or less, preferably 500 μm or less. In the present embodiment, the electrode 1 has a substrate film 2, a metal base layer 3, and a conductive carbon layer 4 in sequence on one side facing the thickness direction. Preferably, the electrode 1 only has the substrate film 2, the metal base layer 3, and the conductive carbon layer 4.

[0021] 1.1 Base film 2

[0022] The substrate film 2 extends in the surface direction. As the material of the substrate film 2, for example, resins and ceramics can be cited. As the material of the substrate film 2, from the viewpoint of ensuring flexibility, resins can be preferably cited. The resin has flexibility. As the resin, for example, polyester resins, acetate resins, polyethersulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, (meth) acrylic resins, polyvinyl chloride resins, polyvinylidene chloride resins, polystyrene resins, polyvinyl alcohol resins, polyarylate resins and polyphenylene sulfide resins can be cited. The resin can be used alone or in combination. As the resin, polyester resins can be preferably cited, and polyethylene terephthalate can be preferably cited. The thickness of the substrate film 2 is, for example, more than 1.9 μm, preferably more than 9 μm, and, for example, less than 999 μm, preferably less than 499 μm.

[0023] 1.2 Metal base layer 3

[0024] The metal base layer 3 is disposed between the base film 2 and the conductive carbon layer 4. The metal base layer 3 is disposed on one surface of the base film 2 in the thickness direction. The metal base layer 3 is in contact with one surface of the base film 2 in the thickness direction. The metal base layer 3 extends in the surface direction.

[0025] The metal base layer 3 assists the conductivity of the conductive carbon layer 4 in the electrode 1. Examples of the material of the metal base layer 3 include titanium, niobium, tantalum, chromium, molybdenum, and tungsten. The materials of the metal base layer 3 may be used alone or in combination. From the viewpoint of the stability of the electrode 1, the material of the metal base layer 3 preferably includes titanium and niobium, and more preferably includes niobium. The thickness of the metal base layer 3 is, for example, 3 nm or more, preferably 6 nm or more, and, for example, 100 nm or less, preferably 30 nm or less.

[0026] 1.3 Conductive carbon layer 4

[0027] The conductive carbon layer 4 is disposed on one surface of the metal base layer 3 in the thickness direction. The conductive carbon layer 4 is in contact with one surface of the metal base layer 3 in the thickness direction. In other words, the metal base layer 3 is in contact with the other surface of the conductive carbon layer 4 in the thickness direction. The conductive carbon layer 4 extends in the surface direction.

[0028] The water contact angle of one surface of the conductive carbon layer 4 in the thickness direction is less than 80 degrees.

[0029] When the water contact angle of one surface of the conductive carbon layer 4 in the thickness direction exceeds 80 degrees, the sensitivity of the electrode 1 becomes insufficient.

[0030] The water contact angle of one surface of the conductive carbon layer 4 in the thickness direction is preferably 70 degrees or less, more preferably 60 degrees or less, further preferably 50 degrees or less, particularly preferably 45 degrees or less, most preferably 40 degrees or less, further preferably 35 degrees or less, further preferably 30 degrees or less, further preferably 25 degrees or less, further preferably 20 degrees or less, further preferably 17 degrees or less, further preferably 15 degrees or less. When the water contact angle of one surface of the conductive carbon layer 4 in the thickness direction is below the above upper limit, the sensitivity of the electrode 1 can be further improved.

[0031] The lower limit of the water contact angle of one surface of the conductive carbon layer 4 in the thickness direction is not limited. The water contact angle of one surface of the conductive carbon layer 4 in the thickness direction is, for example, greater than 0 degrees, further, greater than 1 degree, further, greater than 5 degrees, and further, greater than 10 degrees. When the water contact angle of one surface of the conductive carbon layer 4 in the thickness direction exceeds the above lower limit, the droplet can be measured on the electrode 1.

[0032] There is no limitation on the method for making the water contact angle of one surface of the electrical conductive carbon layer 4 in the thickness direction fall within the above-mentioned range.

[0033] The ratio of nitrogen to carbon (N / C) on one surface of the conductive carbon layer 4 in the thickness direction is not limited. The ratio of nitrogen to carbon (N / C) on one surface of the conductive carbon layer 4 in the thickness direction is, for example, 0.001 or more, preferably 0.005 or more, more preferably 0.009 or more, further preferably 0.010 or more, particularly preferably 0.015 or more, most preferably 0.020 or more, further preferably 0.025 or more, further preferably 0.030 or more. When the ratio of nitrogen to carbon (N / C) on one surface of the conductive carbon layer 4 in the thickness direction is greater than the above lower limit, the sensitivity of the electrode 1 can be further improved.

[0034] The upper limit of the ratio of nitrogen to carbon (N / C) on one surface of the conductive carbon layer 4 in the thickness direction is, for example, 0.5. When the ratio of nitrogen to carbon (N / C) on one surface of the conductive carbon layer 4 in the thickness direction is below the upper limit, the structure as a carbon layer can be maintained.

[0035] The ratio of nitrogen to carbon (N / C) of one surface of the electrical conductive carbon layer 4 in the thickness direction is measured using X-ray photoelectron spectroscopy. The conditions of the X-ray photoelectron spectroscopy are described in the examples described later.

[0036] The conductive carbon layer 4 may include, for example, sp 2 Key and sp 3 The electrical conductive carbon layer 4 has sp 2 Key and sp 3 In the case of bonding, the conductive carbon layer 4 has a graphite structure and a diamond structure. This can improve the sensitivity of the electrode 1 and also provide excellent strength. 3 The number of atoms in the bond relative to sp 3 Bond atomic number and sp 2 The ratio of the total number of atoms in the bond is, for example, 0.1 or more and 0.9 or less.

[0037] The thickness of the conductive carbon layer 4 is, for example, greater than or equal to 0.1 nm, preferably greater than or equal to 1 nm, and less than or equal to 100 nm, preferably less than or equal to 50 nm.

[0038] 1.4 Method for manufacturing electrode 1

[0039] Next, a method for manufacturing the electrode 1 will be described.

[0040] In this method, first, the base film 2 is prepared.

[0041] Next, in this method, a metal base layer 3 is formed on one surface of the base film 2 in the thickness direction. In this embodiment, sputtering is used to form the metal base layer 3. In this embodiment, magnetron sputtering is preferably used. As a sputtering material, the above-mentioned material for the metal base layer 3 can be used.

[0042] It should be noted that the device for sputtering can be driven in advance. Thus, the inside of the device can be made into a state where sputtering is possible. Since the above-mentioned driving is performed before sputtering, it is called "pre-sputtering". The conditions for pre-sputtering are the same as those for sputtering when forming the metal base layer 3.

[0043] Next, in this method, the conductive carbon layer 4 is formed on one surface of the metal base layer 3 in the thickness direction. In this embodiment, sputtering is used to form the conductive carbon layer 4. In this embodiment, magnetron sputtering is preferably used. As a sputtering material, sintered carbon can be used.

[0044] It should be noted that the above-mentioned conductive carbon layer 4 does not yet have the above-mentioned ratio of nitrogen to carbon (N / C).

[0045] Next, in the method of the present embodiment, one surface of the conductive carbon layer 4 in the thickness direction is subjected to a hydrophilic treatment, for example.

[0046] As a method for hydrophilizing one surface of the conductive carbon layer 4 in the thickness direction, for example, there is a method of introducing a hydrophilic element and / or a hydrophilic group into one surface of the conductive carbon layer 4 in the thickness direction.

[0047] Examples of the hydrophilic element include nitrogen, oxygen, and silicon. Preferred hydrophilic elements include nitrogen and oxygen.

[0048] Examples of the hydrophilic group include a hydroxyl group, an amino group, and a carbonyl group. Preferably, the hydrophilic group includes a hydroxyl group.

[0049] The following describes a method for introducing nitrogen and oxygen as hydrophilic elements into one surface of the conductive carbon layer 4 in the thickness direction.

[0050] In this method, for example, nitrogen plasma treatment, atmospheric pressure plasma, low-pressure high-frequency plasma, and low-pressure microwave plasma are exemplified, and preferably, nitrogen plasma treatment is exemplified.

[0051] It should be noted that oxygen plasma treatment cannot introduce hydrophilic elements and / or hydrophilic groups into one surface of the conductive carbon layer 4 in the thickness direction. Therefore, it is impossible to perform hydrophilic treatment on one surface of the conductive carbon layer 4 in the thickness direction, and is therefore not suitable for the present invention.

[0052] The atmospheric pressure is a pressure at which the atmosphere is not intentionally decompressed during plasma generation, and is, for example, 0.05 MPa to 0.15 MPa, and specifically, about 0.1 MPa.

[0053] In the nitrogen plasma treatment, one surface of the electrical conductive carbon layer 4 is exposed to plasma generated in a nitrogen atmosphere.

[0054] In the nitrogen plasma treatment, a plasma generating device (not shown) is used. Although not shown, the plasma generating device includes, for example, a workbench, a nozzle, a gas supply device, and an application unit. The workbench can carry the conductive carbon layer 4. The nozzle can move relative to the workbench. The gas supply device can supply nitrogen gas into the nozzle. The application unit is arranged in the nozzle. The device electrode can apply a voltage to the nitrogen gas in the nozzle.

[0055] The laminate of the substrate film 2, the metal base layer 3 and the conductive carbon layer 4 is placed on a stage. While nitrogen gas is supplied from a gas supply device into the nozzle, a voltage is applied to the nitrogen gas in the nozzle by the device electrode to generate plasma from the nozzle. While irradiating one surface of the conductive carbon layer 4 with plasma, the nozzle is moved relative to the stage.

[0056] It should be noted that the introduction of nitrogen into one surface of the conductive carbon layer 4 in the thickness direction can be confirmed, for example, by the ratio of nitrogen to carbon (N / C) of one surface of the conductive carbon layer 4 in the thickness direction being above the above-mentioned lower limit.

[0057] Thus, the electrode 1 including the base film 2, the metal base layer 3, and the conductive carbon layer 4 having one surface nitrided is manufactured.

[0058] 1.5 Purpose

[0059] The application of the electrode 1 is not limited. The electrode 1 can be preferably used as an electrode for electrochemical measurement in electrochemical measurement, and specifically, can be used as a working electrode (working pole) in cyclic voltammetry (CV).

[0060] Examples of the object of electrochemical measurement (measurement object) include glucose, ferrocene, phenanthrolinedione, methylene blue, 1-methoxy PMS, NADH, p-nitroaniline, p-aminophenol, ethanol, lactic acid, and β-hydroxybutyric acid. Preferably, glucose is used as the object of electrochemical measurement.

[0061] 1.6 Electrochemical measurement system

[0062] Reference Figure 2 , an embodiment of the electrochemical measurement system of the present invention is described.

[0063] The electrochemical measurement system 10 includes a working electrode 11 , a reference electrode 12 , a counter electrode 13 , a potentiostat 14 , and an ammeter (not shown).

[0064] The working electrode 11 includes the electrode 1 described above. In the present embodiment, preferably, the working electrode 11 is an enzyme electrode 7. Specifically, the enzyme electrode 7 includes the electrode 1 described above, and an enzyme layer 5. In other words, the electrochemical measurement system 10 includes the electrode 1 described above. The enzyme layer 5 is disposed on one surface of the conductive carbon layer 4 in the thickness direction. The enzyme layer 5 is in contact with one surface of the conductive carbon layer 4 in the thickness direction. The enzyme layer 5 contains, for example, an enzyme, an immobilizing agent, and a buffer. As an oxidase, for example, glucose dehydrogenase can be cited. As an immobilizing agent, for example, albumin and glutaraldehyde can be cited. As a buffer, for example, a phosphate compound can be cited.

[0065] Examples of the reference electrode 12 include a silver / silver chloride electrode, a saturated calomel electrode, and a standard hydrogen electrode.

[0066] Examples of the counter electrode 13 include a platinum electrode, a gold electrode, and a nickel electrode.

[0067] The working electrode 11, the reference electrode 12 and the counter electrode 13 can be immersed in the object liquid 15. The object liquid 15 contains the above-mentioned measurement object and medium, buffer solution and electrolyte. As the medium, for example, potassium ferrocyanide can be cited. As the buffer solution, for example, a phosphoric acid compound can be cited. As the electrolyte, for example, potassium chloride can be cited.

[0068] 2. Effects

[0069] According to the electrode 1, the water contact angle of one surface of the conductive carbon layer 4 in the thickness direction is as low as 80 degrees or less. Therefore, the electrode 1 has excellent sensitivity to the measurement object. In particular, the electrode 1 has excellent sensitivity to glucose.

[0070] As the above-mentioned mechanism of action, for example, the following is speculated [1].

[0071] [1] If the water contact angle of one surface of the conductive carbon layer 4 in the thickness direction is lower than 80 degrees, when the target liquid containing the measurement object contacts the one surface in the form of a drop, it spreads in the surface direction on the one surface of the conductive carbon layer 4, and on the other hand, it is not easy to bulge toward one side in the thickness direction. Therefore, the distance between the one surface of the conductive carbon layer 4 and the measurement object can be shortened. Therefore, the efficiency of the electrode reaction between the one surface and the measurement object is improved. As a result, the sensitivity of the electrode 1 to the measurement object is improved.

[0072] 3. Modifications

[0073] In the modification, the same reference numerals are used for the same components as those in the first embodiment, and detailed description thereof is omitted. In addition, unless otherwise specified, the modification can exert the same effects as those in the first embodiment. In addition, the first embodiment and its modification can be appropriately combined.

[0074] Although not shown, the electrode 1 may not include the metal base layer 3 .

[0075] Although not shown, the electrode 1 may include two metal base layers 3 and two conductive carbon layers 4. Specifically, the electrode 1 includes the conductive carbon layer 4, the metal base layer 3, the base film 2, the metal base layer 3 and the conductive carbon layer 4 in this order on one side in the thickness direction.

[0076] In one embodiment, the step of forming the conductive carbon layer 4 and the step of hydrophilizing one surface of the conductive carbon layer 4 are performed separately. However, the step of forming the conductive carbon layer 4 with one surface hydrophilized in one step may be performed. For example, the conductive carbon layer 4 is formed by sputtering using a sputtering gas containing nitrogen and oxygen.

[0077] Example

[0078] The following examples and comparative examples are shown to more specifically illustrate the present invention. It should be noted that the present invention is not limited by any of the examples and comparative examples. In addition, the specific numerical values ​​such as the mixing ratio (containing ratio), physical property values, and parameters used in the following descriptions can be replaced by the upper limit value (defined as the numerical value of "below", "less than") or the lower limit value (defined as the numerical value of "above", "exceeding") of the corresponding mixing ratio (containing ratio), physical property values, and parameters recorded in the above-mentioned "Specific Implementation Methods".

[0079] Example 1

[0080] A base film 2 made of polyethylene terephthalate and having a thickness of 188 μm was prepared.

[0081] Next, magnetron sputtering was used to form a metal underlayer 3 made of titanium on one surface of the base film 2 in the thickness direction. The conditions of the magnetron sputtering were as follows.

[0082] Target material: Titanium

[0083] Target power: 3.3W / cm 2

[0084] Sputtering gas: Argon

[0085] Sputtering chamber pressure: 0.2Pa

[0086] The thickness of the metal base layer 3 is 8 nm.

[0087] Next, the conductive carbon layer 4 is formed on one surface of the metal base layer 3 in the thickness direction by magnetron sputtering. The conditions of the magnetron sputtering are as follows.

[0088] Target material: sintered carbon

[0089] Target power: 3.3W / cm 2

[0090] Sputtering gas: Argon

[0091] Sputtering chamber pressure: 0.2Pa

[0092] The thickness of the conductive carbon layer 4 is 10 nm.

[0093] Then, one surface of the conductive carbon layer 4 in the thickness direction is treated. Specifically, one surface of the conductive carbon layer 4 in the thickness direction is subjected to nitrogen plasma treatment at atmospheric pressure (0.1 MPa). Nitrogen plasma is low-temperature plasma. The conditions of the nitrogen plasma treatment are described below.

[0094] Atmosphere gas: Nitrogen

[0095] Nozzle moving speed relative to the conductive carbon layer 4: 500 mm / min

[0096] Plasma gas flow rate: 60SCCM

[0097] Thus, the electrode 1 including the base film 2, the metal base layer 3, and the conductive carbon layer 4 one surface of which was treated with nitrogen plasma was manufactured.

[0098] Example 2 to Example 4

[0099] The electrode 1 was manufactured in the same manner as in Example 1. However, the moving speed of the nozzle relative to the electrical conductive carbon layer 4 was changed as shown in Table 1.

[0100] Example 5

[0101] A base film 2 made of polyethylene terephthalate and having a thickness of 188 μm was prepared.

[0102] Next, magnetron sputtering was used to form a metal underlayer 3 made of niobium on one surface of the base film 2 in the thickness direction. The conditions of the magnetron sputtering were as follows.

[0103] Target: Niobium

[0104] Target power: 4.1W / cm 2

[0105] Sputtering gas: Argon

[0106] Sputtering chamber pressure: 0.2Pa

[0107] The thickness of the metal base layer 3 is 23 nm.

[0108] Next, the conductive carbon layer 4 is formed on one surface of the metal base layer 3 in the thickness direction by magnetron sputtering. The conditions of the magnetron sputtering are as follows.

[0109] Target material: sintered carbon

[0110] Target power: 3.3W / cm 2

[0111] Sputtering gas: Argon

[0112] Sputtering chamber pressure: 0.2Pa

[0113] The thickness of the conductive carbon layer 4 is 5 nm.

[0114] Then, one surface of the conductive carbon layer 4 in the thickness direction is treated. Specifically, one surface of the conductive carbon layer 4 in the thickness direction is subjected to nitrogen plasma treatment at atmospheric pressure (0.1 MPa). Nitrogen plasma is low-temperature plasma. The conditions of the nitrogen plasma treatment are described below.

[0115] Atmosphere gas: Nitrogen

[0116] Nozzle moving speed relative to the conductive carbon layer 4: 400 mm / min

[0117] Plasma gas flow rate: 60SCCM

[0118] Thus, the electrode 1 including the base film 2, the metal base layer 3, and the conductive carbon layer 4 one surface of which was treated with nitrogen plasma was manufactured.

[0119] Embodiment 6 and Embodiment 7

[0120] The electrode 1 was manufactured in the same manner as in Example 5. However, the moving speed of the nozzle relative to the electrical conductive carbon layer 4 was changed as shown in Table 1.

[0121] Comparative Example 1

[0122] The electrode 1 was manufactured by the same treatment as in Example 1. However, the nitrogen plasma treatment under atmospheric pressure was not performed on one surface of the electrical conductive carbon layer 4 .

[0123] Comparative Example 2

[0124] The electrode 1 was manufactured by performing the same treatment as in Example 1. However, the oxygen plasma treatment was performed instead of the nitrogen plasma treatment.

[0125] [evaluate]

[0126] The following items were evaluated about the electrode 1 of each example and each comparative example. The results are shown in Table 1.

[0127] <Water contact angle of one surface of the electrical conductive carbon layer 4 in the thickness direction>

[0128] The water contact angle of one surface of the conductive carbon layer 4 in the thickness direction was measured using a sliding contact angle meter.

[0129] <Ratio of nitrogen to carbon in one surface of the electrical conductive carbon layer in the thickness direction (N / C)>

[0130] The electrode 1 was cut into a size of about 1 cm square and fixed on a sample stand. One surface of the conductive carbon layer 4 in the thickness direction was evaluated by X-ray photoelectron spectroscopy. Specifically, a wide scan measurement was performed on one surface of the conductive carbon layer 4 in the thickness direction to perform a qualitative analysis. At the same time, a narrow scan measurement was performed on the C element and the N element to calculate the element ratio (atomic%, atomic%) and the ratio of nitrogen to carbon (N / C).

[0131] <X-ray photoelectron spectrometer and X-ray photoelectron spectroscopy measurement>

[0132] X-ray photoelectron spectrometer: Quantera SXM manufactured by ULVAC-PHI

[0133] X-ray source: monochromatic Al Kα

[0134] X-ray setting: [15kV, 25W]

[0135] Photoelectron extraction angle: 45 degrees relative to the sample surface

[0136] Charge neutralization conditions: Use neutralization gun and Ar ion gun together (neutralization mode)

[0137] Accelerating voltage of Ar ion gun: 1kV

[0138] Ar ion gun grating size: 1mm×1mm

[0139] In each of the electrodes 1 of Comparative Examples 1 and 2, N element was not detected.

[0140] The lower limit of detection of the ratio of nitrogen to carbon (N / C) in the above measurement is 0.0001.

[0141] [Preparation of enzyme electrode 7]

[0142] First, 0.8 mg of glucose dehydrogenase, 1.5 μL of a 4 wt % aqueous solution of bovine serum albumin, 1.2 μL of a 1 % aqueous solution of glutaraldehyde, and 0.3 μL of a 0.05 M potassium phosphate buffer (pH 6.5) were mixed to prepare an enzyme solution.

[0143] Next, an insulating tape with a hole of 2 mm in diameter was pasted on one surface of the electrode 1 in the thickness direction to produce an electrode 1 with a known exposed area on one surface. Next, the enzyme solution was dripped onto the electrode 1 and stored in a refrigerator at 3°C ​​for more than one night. Thus, an enzyme electrode (enzyme-modified carbon electrode) 7 having an electrode 1 and an enzyme layer 5 was produced.

[0144] [Measurement of glucose response current]

[0145] The object solution 15 was prepared. Specifically, a 100 mM potassium ferrocyanide solution, an electrolyte solution obtained by adding KCl to a 0.05 M phosphate buffer (pH 6.5) to make it 1 M, and a 1000 mg / dL glucose solution were mixed according to the formula in Table 2 to prepare glucose solutions having concentrations of 0 mg / dL, 100 mg / dL, 200 mg / dL, 400 mg / dL, and 600 mg / dL.

[0146] Next, the enzyme electrode (enzyme modified carbon electrode) 7 is used as the working electrode 11, as shown in FIG. Figure 2 As shown, the working electrode 11 is connected to a constant potential meter 14 (manufactured by IVIUM Technologies, pocketSTAT) together with a reference electrode 12 (Ag / AgCl) and a counter electrode 13 (Pt), and an electrochemical measurement system 10 equipped with them is produced. Next, 1 mL of glucose solution of each concentration is developed on the enzyme-modified carbon electrode for 1 minute. Then, for the working electrode 11 of these electrochemical measurement systems 10, the scanning speed is set to 0.1 V / sec in the range of the potential scanning range of -0.2 to 0.8 V, and cyclic voltammetry (CV) is performed. According to the results of the CV measurement, the current value of the glucose concentration of 600 mg / dl at 0.3 V relative to the current value of 0 mg / dl is used as the signal-to-background ratio. The S / N ratio is evaluated according to the following criteria.

[0147] A: S / N ratio is 50 or more. The sensitivity to glucose is significantly excellent.

[0148] B: The S / N ratio is 35 or more and less than 50. The sensitivity to glucose is excellent.

[0149] C: The S / N ratio is 30 or more and less than 35. The sensitivity to glucose is slightly excellent.

[0150] D: S / N ratio is less than 30. The sensitivity to glucose is insufficient.

[0151] <Considerations of Example 1 and Comparative Example 2>

[0152] In the oxygen plasma treatment of Comparative Example 2, carbon dioxide was generated and plasma effective for hydrophilization could not be maintained, so hydrophilization treatment could not be achieved on one surface of the electrical conductive carbon layer 4 in the thickness direction. As a result, the estimated sensitivity evaluation was D.

[0153] In contrast, in the nitrogen plasma treatment of Example 1, carbon dioxide was not generated, and plasma effective for hydrophilization was maintained, so that one surface of the electrical conductive carbon layer 4 in the thickness direction could be hydrophilized. As a result, the estimated sensitivity evaluation was A.

[0154] [Table 1]

[0155]

[0156] [Table 2]

[0157] Table 2

[0158]

[0159] It should be noted that the above invention is provided as an exemplary embodiment of the present invention, but it is merely an example and is not to be construed as limiting. Modifications of the present invention that are obvious to those skilled in the art are also included in the appended claims.

[0160] Industrial Applicability

[0161] The electrodes can be used in electrochemical measurement systems.

[0162] Description of Reference Numerals

[0163] 1 Electrode

[0164] 2. Substrate film

[0165] 3 Metal base layer

[0166] 4 Conductive carbon layer

[0167] 7 Enzyme Electrode

[0168] 10 Electrochemical measurement system

[0169] 11 Working electrode

Claims

1. An electrode, which has a substrate film and a conductive carbon layer in this order on one side facing the thickness direction, The water contact angle of one surface of the conductive carbon layer in the thickness direction is less than 80 degrees.

2. The electrode according to claim 1, further comprising a metal base layer disposed between the base film and the conductive carbon layer, The metal base layer is in contact with one surface of the substrate film in the thickness direction and the other surface of the conductive carbon layer in the thickness direction. The electrode according to claim 2 , which is an electrode for electrochemical measurement.

4. An electrochemical measurement system comprising the electrode according to claim 3.

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