Method for quantifying substrate

• US 5,985,130 A
• Filed: 04/03/1997
• Issued: 11/16/1999
• Est. Priority Date: 04/04/1996
• Status: Expired due to Term

• Current Assignee: Panasonic Healthcare Holdings Co., Ltd.
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Ikeda, Shin, Yoshioka, Toshihiko, Nankai, Shiro
• Primary Examiner(s): Tung, T.
• Assistant Examiner(s): NOGUEROLA, ALEXANDER STEPHAN
• Application Number:
  US08/834,829
• Time in Patent Office: 957 Days
• Field of Search: 204/403, 204/406, 204/400, 205/777.5, 435/817
• US Class Current: 205/777.5
• CPC Class Codes: C12Q 1/001 Enzyme electrodes
• CPC Class Codes: G01N 27/3273 Devices therefor, e.g. test element readers, circuitry details not specific to biochemical electrodes G01N33/4875

Abstract

The present invention provides a method for quantifying a substrate having improved measurement accuracy and measurement sensitivity. According to the method for quantifying the substrate of the present invention, a constant voltage is applied to an electrode system, between a working electrode and a counter electrode, via a resistor connected in series with the electrode system after placing a sample solution containing the substrate on the electrode system, so as to oxidize an electron acceptor, which has been reduced by an enzyme reaction of the substrate, thereby determining a concentration of the substrate included in the sample solution based on an oxidizing current flowing in the course of oxidation.

Claims

1. A method for quantifying a substrate comprising the steps of:

bringing a solution containing an enzyme and an electron acceptor into contact with a surface of an electrode system comprising a working electrode and a counter electrode;

adding a sample solution containing a substrate to said solution containing the enzyme and the electron acceptor;

connecting said electrode system to a constant voltage source via a resistor being connected in series to said working electrode in order to apply to said electrode system a voltage which exhibits a temporary drop at said working electrode; and

measuring an electric current flowing through said electrode system for a predetermined time after the application of said voltage.

2. The method for quantifying a substrate in accordance with claim 1, wherein said resistor has a resistance of not less than 1 kΩ

.

3. A method for quantifying a substrate comprising the steps of:

adding a sample solution containing a substrate to a reaction layer formed on a surface of an electrode system comprising a working electrode and a counter electrode, said reaction layer containing an enzyme and an electron acceptor;

connecting said electrode system to a constant voltage source via a resistor being connected in series to said working electrode in order to apply to said electrode system a voltage which exhibits a temporary drop at said working electrode; and

measuring an electric current flowing through said electrode system for a predetermined time after the application of said voltage.

4. The method for quantifying a substrate in accordance with claim 3, wherein said reaction layer further contains a hydrophilic polymer.

5. The method for quantifying a substrate in accordance with claim 3, wherein said resistor has a resistance of not less than 1 kΩ

.