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 ratio of nitrogen to carbon (N / C) of one surface of the conductive carbon layer (4) in the thickness direction, as measured using X-ray photoelectron spectroscopy, is 0.001 or more.

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] comprises an electrode, wherein the electrode has a substrate film and a conductive carbon layer in sequence on one side facing the thickness direction, and the ratio of nitrogen to carbon (N / C) in one surface of the conductive carbon layer in the thickness direction measured using X-ray photoelectron spectroscopy is greater than 0.001.

[0011] The present invention [2] comprises the electrode described in [1], wherein the ratio of nitrogen to carbon (N / C) on the other side of the aforementioned conductive carbon layer in the thickness direction, measured using X-ray electron spectroscopy, is lower than the ratio of nitrogen to carbon (N / C) on the aforementioned one side.

[0012] The present invention [3] comprises the electrode described in [1] or [2], wherein the electrode further comprises a metal base layer arranged between the aforementioned substrate film and the aforementioned conductive carbon layer, wherein 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.

[0013] The present invention [4] comprises the electrode according to any one of [1] to [3], which is an electrode for electrochemical measurement.

[0014] The present invention [5] includes an electrochemical measurement system comprising the electrode according to any one of [1] to [4].

[0015] Effects of the Invention

[0016] According to the present invention, the ratio of nitrogen to carbon (N / C) in one surface of the conductive carbon layer in the thickness direction is 0.001 or more. Therefore, the electrode and the electrochemical measurement system including the electrode have excellent sensitivity to the measurement object. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] [ Figure 1 ] is a cross-sectional view of one embodiment of the electrode of the present invention.

[0018] [ Figure 2 ] is a schematic diagram of one embodiment of the electrochemical measurement system of the present invention. DETAILED DESCRIPTION

[0019] 1. Electrodes

[0020] Reference Figure 1 One embodiment of the electrode of the present invention will be described.

[0021] 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.

[0022] 1.1 Base film 2

[0023] 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.

[0024] 1.2 Metal base layer 3

[0025] 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.

[0026] 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 50 nm or less.

[0027] 1.3 Conductive carbon layer 4

[0028] 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.

[0029] The ratio of nitrogen to carbon (N / C) on one surface of the electrical conductive carbon layer 4 in the thickness direction is greater than or equal to 0.001.

[0030] When the ratio of nitrogen to carbon (N / C) on one surface of the electrical conductive carbon layer 4 in the thickness direction is less than 0.001, the sensitivity of the electrode 1 becomes insufficient.

[0031] The ratio of nitrogen to carbon (N / C) on one surface of the conductive carbon layer 4 in the thickness direction is 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.

[0032] 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 not limited. 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 less than the above upper limit, the structure as a carbon layer can be maintained.

[0033] In the conductive carbon layer 4, the ratio of nitrogen to carbon (N / C) in the other surface is, for example, lower than the ratio of nitrogen to carbon (N / C) in one surface. That is, in the conductive carbon layer 4, the ratio of nitrogen to carbon (N / C) in one surface is higher than the ratio of nitrogen to carbon (N / C) in the other surface. When the ratio of nitrogen to carbon (N / C) in the other surface of the conductive carbon layer 4 is lower than the ratio of nitrogen to carbon (N / C) in one surface, the sensitivity of the electrode 1 can be further improved.

[0034] The ratio of nitrogen to carbon (N / C) on the other side of the conductive carbon layer 4 is, for example, less than 0.001, preferably less than 0.0005, more preferably less than 0.0001, and particularly preferably 0.000.

[0035] There is no limitation on the method for making the ratio of nitrogen to carbon (N / C) in one surface and the other surface of the conductive carbon layer 4 in the thickness direction within the above range. As a method for making the ratio of nitrogen to carbon (N / C) in one surface of the conductive carbon layer 4 in the thickness direction within the above range, for example, a method of nitriding one surface of the conductive carbon layer 4 in the thickness direction, etching, surface modification and cleaning can be cited. In this embodiment, a method of nitriding one surface of the conductive carbon layer 4 in the thickness direction is preferably cited. The method of nitriding one surface is described later.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 1.4 Method for manufacturing electrode 1

[0040] Next, a method for manufacturing the electrode 1 will be described.

[0041] In this method, first, the base film 2 is prepared.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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).

[0046] Next, in the method of this embodiment, one surface of the conductive carbon layer 4 in the thickness direction is subjected to a nitriding treatment, for example. The nitriding treatment is not limited. As the nitriding treatment, for example, nitrogen plasma treatment, reactive sputtering by nitrogen gas, and surface modification other than nitrogen plasma treatment and reactive sputtering by nitrogen gas can be cited. As the nitriding treatment, nitrogen plasma treatment can be preferably cited.

[0047] Examples of the nitrogen plasma treatment include nitrogen plasma treatment under atmospheric pressure, nitrogen plasma treatment under low pressure, high-frequency plasma under low pressure, and microwave plasma under low pressure.

[0048] 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.

[0049] In the nitrogen plasma treatment, one surface of the electrical conductive carbon layer 4 is exposed to plasma generated in a nitrogen atmosphere.

[0050] 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 plasma generating unit, a gas supply device, and an application unit. The workbench can carry the conductive carbon layer 4. The plasma generating unit can move relative to the workbench. The plasma generating unit includes a nozzle. The gas supply device can supply nitrogen gas into the plasma generating unit. The application unit is arranged in the plasma generating unit. The device electrode can apply a voltage to the nitrogen gas in the plasma generating unit.

[0051] 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 to the plasma generating unit, a voltage is applied to the nitrogen gas in the plasma generating unit by the device electrode, and plasma is generated from the plasma generating unit. While irradiating one surface of the conductive carbon layer 4 with plasma, the plasma generating unit is moved relative to the stage.

[0052] 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.

[0053] 1.5 Purpose

[0054] 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).

[0055] Examples of the object of electrochemical measurement (measurement object) include ferrocene, phenanthrolinedione, methylene blue, 1-methoxy PMS, NADH, p-nitroaniline, p-aminophenol, ethanol, lactic acid, β-hydroxybutyric acid, glucose, and potassium ferrocyanide. Preferably, glucose is used as the object of electrochemical measurement.

[0056] 1.6 Electrochemical measurement system

[0057] Reference Figure 2 , an embodiment of the electrochemical measurement system of the present invention is described.

[0058] 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).

[0059] 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.

[0060] Examples of the reference electrode 12 include a silver / silver chloride electrode, a saturated calomel electrode, and a standard hydrogen electrode.

[0061] Examples of the counter electrode 13 include a platinum electrode, a gold electrode, and a nickel electrode.

[0062] 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.

[0063] 2. Effects

[0064] According to the electrode 1, the ratio of nitrogen to carbon (N / C) on one surface of the conductive carbon layer 4 in the thickness direction is as high as 0.001 or more. Therefore, the electrode 1 has excellent sensitivity to the measurement object. In particular, the electrode 1 has excellent sensitivity to glucose.

[0065] As the above-mentioned mechanism of action, for example, the following [1] and / or [2] are speculated.

[0066] [1] One surface of the conductive carbon layer 4 in the thickness direction is easily cationic by nitridation. On the other hand, when the object to be measured coexists with potassium ferrocyanide as a medium in an electrolyte, the medium is ionized in the electrolyte to form anions ([Fe(CN) 6 ) 4- ). Then, the cationic surface and the anion mentioned above come close to each other based on electrostatic interaction. Thus, the sensitivity of the electrode 1 to the measurement object is improved.

[0067] [2] In one surface of the conductive carbon layer 4 in the thickness direction, a portion of the carbon arrangement is replaced by nitrogen, thereby easily generating negative carriers (charged particles). As a result, with the generation of negative carriers, the electron transfer efficiency in one surface of the conductive carbon layer 4 becomes higher, and the electron transfer efficiency between the conductive carbon layer 4 and the potassium ferrocyanide increases. Therefore, the sensitivity of the electrode 1 to the measured object is improved.

[0068] 3. Modifications

[0069] 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.

[0070] Although not shown, the electrode 1 may not include the metal base layer 3 .

[0071] 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.

[0072] Example

[0073] 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".

[0074] Example 1

[0075] A base film 2 made of polyethylene terephthalate and having a thickness of 188 μm was prepared.

[0076] 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.

[0077] Target material: Titanium

[0078] Target power: 3.3W / cm 2

[0079] Sputtering gas: Argon

[0080] Sputtering chamber pressure: 0.2Pa

[0081] The thickness of the metal base layer 3 is 8 nm.

[0082] 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.

[0083] Target material: sintered carbon

[0084] Target power: 3.3W / cm 2

[0085] Sputtering gas: Argon

[0086] Sputtering chamber pressure: 0.2Pa

[0087] The thickness of the conductive carbon layer 4 is 10 nm.

[0088] Then, one surface of the electrical conductive carbon layer 4 in the thickness direction is subjected to a nitrogen plasma treatment at atmospheric pressure (0.1 MPa). Nitrogen plasma is a low-temperature plasma. The conditions of the nitrogen plasma treatment are described below.

[0089] Atmosphere gas: Nitrogen

[0090] Movement speed of the plasma generating unit relative to the conductive carbon layer 4: 500 mm / min Plasma gas flow rate: 60 SCCM

[0091] 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.

[0092] Example 2 to Example 4

[0093] The electrode 1 was manufactured in the same manner as in Example 1. However, the moving speed of the plasma generating part relative to the electrical conductive carbon layer 4 was changed as shown in Table 1.

[0094] Example 5

[0095] A base film 2 made of polyethylene terephthalate and having a thickness of 188 μm was prepared.

[0096] 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.

[0097] Target: Niobium

[0098] Target power: 4.1W / cm 2

[0099] Sputtering gas: Argon

[0100] Sputtering chamber pressure: 0.2Pa

[0101] The thickness of the metal base layer 3 is 23 nm.

[0102] 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.

[0103] Target material: sintered carbon

[0104] Target power: 3.3W / cm 2

[0105] Sputtering gas: Argon

[0106] Sputtering chamber pressure: 0.2Pa

[0107] The thickness of the conductive carbon layer 4 is 5 nm.

[0108] 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.

[0109] Atmosphere gas: Nitrogen

[0110] Nozzle moving speed relative to the conductive carbon layer 4: 400 mm / min

[0111] Plasma gas flow rate: 60SCCM

[0112] 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.

[0113] Example 6

[0114] 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.

[0115] Comparative Example 1

[0116] 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 .

[0117] Comparative Example 2

[0118] 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.

[0119] [evaluate]

[0120] The following items were evaluated about the electrode 1 of each example and each comparative example. The results are shown in Table 1.

[0121] <Ratio of nitrogen to carbon on one surface and the other surface of the electrical conductive carbon layer 4 in the thickness direction (N / C)>

[0122] 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 was calculated as the N / C ratio.

[0123] The N / C ratio was calculated for the ratio of nitrogen to carbon at a thickness (depth) of 10 nm (corresponding to the other side) while etching was performed using an Ar ion gun. 2 Calculate by converting the thickness (depth) of the gauge.

[0124] <X-ray photoelectron spectrometer and X-ray photoelectron spectroscopy measurement>

[0125] X-ray photoelectron spectrometer: Quantera SXM manufactured by ULVAC-PHI

[0126] X-ray source: monochromatic Al Kα

[0127] X-ray setting: [15kV, 25W]

[0128] Photoelectron extraction angle: 45 degrees relative to the sample surface

[0129] Charge neutralization conditions: Use neutralization gun and Ar ion gun together (neutralization mode)

[0130] Accelerating voltage of Ar ion gun: 1kV

[0131] Ar ion gun grating size: 1mm×1mm

[0132] Etching speed of Ar ion gun: According to SiO 2 Conversion meter 4nm / min

[0133] In the electrodes 1 of Comparative Examples 1 and 2, the N element was not detected.

[0134] The lower limit of detection of the ratio of nitrogen to carbon (N / C) in the above measurement is 0.0001.

[0135] [Preparation of enzyme electrode 7]

[0136] 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.

[0137] 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.

[0138] [Measurement of glucose response current]

[0139] 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.

[0140] 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.

[0141] A: S / N ratio is 50 or more. The sensitivity to glucose is significantly excellent.

[0142] B: The S / N ratio is 35 or more and less than 50. The sensitivity to glucose is excellent.

[0143] C: The S / N ratio is 30 or more and less than 35. The sensitivity to glucose is slightly excellent.

[0144] D: S / N ratio is less than 30. The sensitivity to glucose is insufficient.

[0145] [Table 1]

[0146]

[0147] [Table 2]

[0148] Table 2

[0149]

[0150] 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.

[0151] Industrial Applicability

[0152] Electrodes are used in electrochemical measurement systems.

[0153] Description of Reference Numerals

[0154] 1 Electrode

[0155] 2. Substrate film

[0156] 3 Metal base layer

[0157] 4 Conductive carbon layer

[0158] 7 Enzyme Electrode

[0159] 10 Electrochemical measurement system

[0160] 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 ratio of nitrogen to carbon (N / C) in one surface of the conductive carbon layer in the thickness direction measured using X-ray photoelectron spectroscopy is greater than 0.

001.

2. The electrode according to claim 1, wherein The ratio of nitrogen to carbon (N / C) on the other side of the conductive carbon layer in the thickness direction, measured using X-ray electron spectroscopy, is lower than the ratio of nitrogen to carbon (N / C) on the one side.

3. The electrode according to claim 1 or 2, 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 3 , which is an electrode for electrochemical measurement.

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

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