Voltage applying method for hydrogen-type enzyme electrode

• US 5,556,533 A
• Filed: 06/06/1995
• Issued: 09/17/1996
• Est. Priority Date: 08/03/1993
• Status: Expired due to Fees

• Current Assignee: A&D Company Limited (A&D Holon Holdings Co Ltd)
• Original Assignee: A&D Company Limited (A&D Holon Holdings Co Ltd)
• Inventors: Murata, Kazuharu, Nozoe, Yoshiteru
• Primary Examiner(s): Bell, Bruce F.
• Application Number:
  US08/471,779
• Time in Patent Office: 469 Days
• Field of Search: 205/777.5, 204/403, 204/412, 435/817, 435/291, 435/288, 435/289
• US Class Current: 205/777.5
• CPC Class Codes: C12Q 1/001 Enzyme electrodes
• CPC Class Codes: C12Q 1/002 Electrode membranes
• CPC Class Codes: G01N 33/4875 Details of handling test elements, e.g. dispensing or storage, not specific to a particular test method test-elements per se B01L, automatic analysers G01N35/00, in-vivo analysis on the human body for medical diagnosis A61B
• CPC Class Codes: Y10S 435/817 Enzyme or microbe electrode

Abstract

A voltage applying method for a hydrogen type enzyme electrode in a chemical sensor and using a pair of working electrodes, a reference electrode and a counter electrode includes detecting a contact of a test specimen with the enzyme electrode; keeping a potential applied to the working electrodes at a first potential of substantially zero for a first preset time; applying a second potential that is higher than a hydrogen peroxide detect potential to the working electrodes for a second preset time; dropping the second potential to a third potential below zero potential; and sweeping from the first potential to a fourth potential higher than said hydrogen peroxide detect potential at a fixed rate. Other variations of the method are disclosed.

Claims

1. A voltage applying method for a hydrogen enzyme electrode having a pair of working electrodes, a reference electrode and a counter electrode comprising:

detecting a contact of a test specimen with said enzyme electrode;

keeping a potential applied to said working electrodes at a first potential of substantially zero for a first preset time;

applying a second potential which is higher than a hydrogen peroxide detect potential to said working electrodes for a second preset time;

dropping said second potential to a third potential below zero potential;

sweeping from said third potential to a fourth potential higher than said hydrogen peroxide detect potential at a fixed rate.

2. A voltage applying method according to claim 1, wherein said detecting step comprising:

applying a preset potential to said pair of working electrodes;

detecting a preset current between said pair of working electrodes and said counter electrode to confirm as to whether enzyme electrode contacts said test specimen.

3. A voltage applying method according to claim 1, wherein said first preset time is substantially 15 to 40 seconds.

4. A voltage applying method according to claim 1, wherein said hydrogen peroxide detect potential is substantially 600 mV.

5. A voltage applying method according to claim 4, wherein said third potential is substantially -400 to -200 mV.

6. A voltage applying method according to claim 1, wherein said fixed rate is substantially 100 mV/sec.

7. A voltage applying method according to claim 1, further comprising said value:

simultaneously with said sweeping step, detecting one of a peak value of current in the range of the voltage sweep to said fourth potential, a current value at a potential separated from a potential causing the peak current value by a preset potential value, and a current value at a specific potential; and

converting said detected current value into a concentration of a substance in said test specimen by comparing with a calibration curve previously charted.

8. A voltage applying method for a hydrogen enzyme electrode having a pair of working electrodes, a reference electrode and a counter electrode comprising:

detecting a contact of a test specimen with said enzyme electrode;

keeping a potential applied to said working electrodes at a first potential of substantially zero for a first preset time;

flowing a first current which is larger than a hydrogen peroxide detect current to said working electrodes for a second preset time;

dropping to a second potential below zero potential;

sweeping from said second potential to a third potential higher than said hydrogen peroxide detect potential at a fixed rate.

9. A voltage applying method according to claim 8, wherein said detecting step comprising:

applying a preset potential to said pair of working electrodes;

detecting a preset current between said pair of working electrodes and said counter electrode to confirm enzyme electrode contact with said test specimen.

10. A voltage applying method according to claim 8, further comprising:

simultaneously with said sweeping step, detecting one of a peak value of current in the range of the voltage sweep to said fourth potential, a current value at a potential separated from a potential causing the peak current value by a preset potential value, and a current value at a specific potential; and

converting said detected current value into a concentration of a substance in said test specimen by comparing said value with a calibration curve previously charted.

11. A voltage applying method according to claim 8, further comprising, before dropping to a second potential step, keeping a final potential that is reached when said preset time is passed at a third preset time.

12. A voltage applying method according to claim 11, further comprising:

simultaneously with said sweeping step, detecting one of a peak value of current in the range of the voltage sweep to said fourth potential, a current value at a potential separated from a potential causing the peak current value by a preset potential value, and a current value at a specific potential; and

converting said detected current value into a concentration of a substance in said test specimen by comparing said value with a calibration curve previously charted.