Apparatus for maintaining the activity of an enzyme electrode

• US 5,288,387 A
• Filed: 06/10/1991
• Issued: 02/22/1994
• Est. Priority Date: 06/12/1990
• Status: Expired due to Fees

• Current Assignee: Sankyo Company Limited (Daiichi Sankyo Company Limited)
• Original Assignee: Daikin Industries Ltd
• Inventors: Ito, Takayuki, Katayama, Hideo
• Primary Examiner(s): Tung, T.
• Application Number:
  US07/712,669
• Time in Patent Office: 988 Days
• Field of Search: 204/400, 204/402, 204/403, 204/415
• US Class Current: 204/402
• CPC Class Codes: C12Q 1/001 Enzyme electrodes

Abstract

A concentration measuring apparatus includes an enzyme electrode which accelerates an oxidation reaction or a reduction reaction of a test substance in a liquid and outputs an electrical signal corresponding to a quantity of the test substance therefrom due to the reaction. The enzyme electrode is supplied with a reviving voltage for removing interfering substances on the enzyme electrode not only prior to concentration measuring but also according to a predetermined time interval. The reviving voltage has a polarity which is the reverse of the voltage used for concentration measurement.

Claims

1. An apparatus for maintaining activity of an enzyme electrode of a concentration measuring apparatus which measures a concentration of a test substance in a liquid based upon an electrical signal output from said enzyme electrode when an oxidation reaction or a reduction reaction of said test substance is performed on said enzyme electrode, said apparatus comprising:

a reviving power source means for applying a reviving voltage to said enzyme electrode for activating said enzyme electrode, said reviving voltage having a polarity which is reverse with respect to a test voltage which is applied to said enzyme electrode for performing concentration measurement;

connection means for interconnecting said reviving power source means and said enzyme electrode;

interconnection instruction means for providing an interconnection signal for causing interconnection of said reviving power source means and said enzyme electrode in response to either a timing signal indicative of expiration of a predetermined time interval or a signal indicative of an instruction to perform a concentration measurement; and

connection controlling means for controlling said connection means to interconnect said reviving power source means and said enzyme electrode in response to an interconnection signal from said interconnection instruction means.

2. An apparatus as set forth in claim 1, further comprising judging means for comparing an electrical signal output from said enzyme electrode and a predetermined threshold value after application of said reviving voltage to said enzyme electrode by said connection means to judge whether or not said enzyme electrode is in an error condition.

3. An apparatus as set forth in claim 2, wherein said judging means judges said enzyme electrode to be in said error condition when an output current from said electrode does not exceed said predetermined threshold value.