Substrate determining method

• US 20050164328A1
• Filed: 03/05/2003
• Published: 07/28/2005
• Est. Priority Date: 03/08/2002
• Status: Abandoned Application

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Nakaminami, Takahiro, Kuwabata, Susumu
• Application Number:
  US10/507,010
• Publication Number:
  US 20050164328A1
• Time in Patent Office: Days
• US Class Current: 435/25
• CPC Class Codes: C12Q 1/001 Enzyme electrodes
• CPC Class Codes: C12Q 1/26 involving oxidoreductase
• CPC Class Codes: C12Q 1/32 involving dehydrogenase
• CPC Class Codes: G01N 27/3273 Devices therefor, e.g. test element readers, circuitry details not specific to biochemical electrodes G01N33/4875

Abstract

There is provided a method for precisely quantitating a substrate by means of a measurement system with a simple structure without occurrence of a measurement error due to an interfering substance. In a method for quantitating a substrate in a sample solution which contains a dissolved interfering substance and the substrate, by the use of an electrode system and a reagent system, (a) a sample solution which contains a dissolved interfering substance and a substrate is supplied to an electrode system comprising a working electrode and a counter electrode under the existence of a reagent system comprising oxidoreductase and an electron mediator; (b) an AC potential is applied to the working electrode, to cause a redox reaction of the electron mediator: (c) an electric signal produced on the basis of the redox reaction is measured by means of the electrode system; and (d) the substrate is quantitated on the basis of the electric signal.

Claims

1. A method for quantitating a substrate in a sample solution, which contains a dissolved interfering substance and said substrate, by the use of an electrode system and a reagent system, comprising the steps of:

(a) supplying a sample solution which contains a dissolved interfering substance and a substrate to an electrode system comprising a working electrode and a counter electrode under the existence of a reagent system comprising oxidoreductase and an electron mediator;

(b) applying an AC potential to said working electrode to cause a redox reaction of said electron mediator;

(c) measuring an electric signal produced on the basis of said redox reaction, by means of said electrode system; and

(d) quantitating said substrate on the basis of said electric signal.

2. The method for quantitating a substrate in accordance with claim 1, characterized in that in said step (a), said working electrode and said counter electrode are disposed on the same plane.

3. The method for quantitating a substrate in accordance with claim 1, characterized in that in said step (a), said working electrode and said counter electrode are disposed in positions opposed to each other across a space.

4. The method for quantitating a substrate in accordance with claim 1, further comprising a step (e) of applying a DC potential to said working electrode, and a step (f) of measuring an electric signal produced in said step (e).

5. The method for quantitating a substrate in accordance with claim 1, characterized in that in said step (b), a central potential of said AC potential is within the range of −

0.4 to +0.4 V relative to a redox potential of said electron mediator, and is a potential more positive than a potential that is 0.05 V negative relative to the most negative potential in a potential region where the reaction of said interfering substance at said working electrode is diffusion-controlled.

6. The method for quantitating a substrate in accordance with claim 1, characterized in that in said step (b), a central potential of said AC potential is within the range of −

0.1 to +0.1 V relative to a redox potential of said electron mediator, and is a potential more positive than a potential that is +0.05 V relative to the most negative potential in a potential region where the reaction of said interfering substance at said working electrode is diffusion-controlled.

7. The method for quantitating a substrate in accordance with claim 1, characterized in that said electric signal is impedance.

8. The method for quantitating a substrate in accordance with claim 1, characterized in that said electrode system further comprises a reference electrode.

9. The method for quantitating a substrate in accordance with claim 1, characterized in that said working electrode is a rotating disc electrode or a micro-electrode.

10. The method for quantitating a substrate in accordance with claim 1, characterized in that said oxidoreductase is glucose oxidase or pyrroloquinoline quinone-dependent glucose dehydrogenase, and said electron mediator is ferrocene carboxylic acid.

11. The method for quantitating a substrate in accordance with claim 1, characterized in that said oxidoreductase is pyloroquinoline quinone-dependent glucose dehydrogenase, and said electron mediator is ruthenium hexacyanate.