Concentration measuring method, concentration test instrument, and concentration measuring apparatus

• US 7,390,391 B2
• Filed: 08/30/2002
• Issued: 06/24/2008
• Est. Priority Date: 09/14/2001
• Status: Expired

• Current Assignee: ARKRAY, Inc
• Original Assignee: ARKRAY, Inc
• Inventors: Yamaoka, Hideaki, Nagakawa, Kenji
• Primary Examiner(s): Olsen; Kaj K
• Application Number:
  US10/489,488
• Publication Number:
  US 20040245121A1
• Time in Patent Office: 2,125 Days
• Field of Search: 204/403.01, 204/403.14, 205/777.5, 205/792
• US Class Current: 205/777.5
• CPC Class Codes: C12Q 1/001 Enzyme electrodes
• CPC Class Codes: C12Q 1/004 mediator-assisted
• CPC Class Codes: G01N 27/3271 Amperometric enzyme electrodes for analytes in body fluids, e.g. glucose in blood amperometry per se G01N27/49; aspects concerning the enzyme reagent C12Q1/001

Abstract

The present invention relates to technology for constructing a reaction system including a test target, an oxidation-reduction enzyme, and an electron mediator, and measuring the concentration of the test target by an electrochemical process. A Ru compound is used as the electron mediator. The present invention provides a concentration test instrument including a substrate, first and second electrodes formed on the substrate, and a reagent layer formed as a solid. The reagent layer contains an oxidation-reduction enzyme and a Ru compound, and is constituted so as to dissolve and construct a liquid phase reaction system when a sample liquid is supplied.

Claims

1. A method for measuring a concentration of a test target, the method comprising:

constructing a reaction system by supplying the test target to a reagent layer containing an oxidation-reduction enzyme and an electron mediator;

measuring the concentration of the test target by utilizing;

wherein the test target is glucose, the oxidation-reduction enzyme is CyGDH, and a Ru compound is used as the electron mediator,

the method further comprising;

applying constant voltage to the reagent layer; and

computing the concentration of the test target on the basis of a response current value from the reagent layer;

wherein the constant voltage is no greater than 300 mV and selected from a range from a standard oxidation-reduction potential (versus a standard hydrogen electrode) between an oxidant and a reductant of the Ru compound through a standard oxidation-reduction potential (versus a standard hydrogen electrode) between ferrocyanide ions and ferricyanide ions.

2. The method according to claim 1, wherein the Ru compound is oxidative Ru(III) complex expressed by the following chemical formula:

[Ru(NH₃)₅X]ⁿ⁺

(where X in the formula is NH₃ or a halogen ion, and n+ in the formula is the valence of the oxidative Ru(III) complex as determined by a type of X).