Method and system for error checking an electrochemical sensor

• US 7,626,401 B2
• Filed: 08/07/2008
• Issued: 12/01/2009
• Est. Priority Date: 10/05/2005
• Status: Active Grant

• Current Assignee: Roche Diagnostics Operations Incorporated (Roche Holding AG)
• Original Assignee: Roche Diagnostics Operations Incorporated (Roche Holding AG)
• Inventors: Unkrig, Volker, Saecker, Sylvia, Dreibholz, Joerg
• Primary Examiner(s): Nguyen; Vincent Q
• Application Number:
  US12/187,451
• Publication Number:
  US 20090027064A1
• Time in Patent Office: 481 Days
• Field of Search: 324/692, 324/439, 324/444, 204/401, 205/792
• US Class Current: 324/692
• CPC Class Codes: G01N 27/3274 Corrective measures, e.g. error detection, compensation for temperature or hematocrit, calibration coding of calibration information G01N33/48771

Abstract

A method and a corresponding system for error checking an electrochemical sensor having at least two electrodes and a liquid measuring medium applied thereto are disclosed. The method discloses determining a first admittance between a first set of electrodes of the sensor; determining a second admittance between a second set of electrodes of the sensor; determining a value using the first admittance and the second admittance; and displaying an error message if the value is out of a predetermined tolerance.

Claims

1. A method for error checking an electrochemical sensor having at least two electrodes and a liquid measuring medium applied thereto comprising:

determining a first admittance between a first set of electrodes of the sensor;

determining a second admittance between a second set of electrodes of the sensor;

determining a value using said first admittance and said second admittance; and

providing an error message if said value is out of tolerance;

determining whether an active electrode surface deviates from specified values based on said first admittance and said second admittance.

2. The method according to claim 1, wherein said first set of electrodes are said second set of electrodes.

3. The method according to claim 1, wherein one of said first set of electrodes is one of said second set of electrodes.

4. The method according to claim 1, wherein none of said first set of electrodes are in said second set of electrodes.

5. The method according to claim 1, further comprising,

determining whether an active electrode surface deviates from specified values based on said first admittance and said second admittance;

and

displaying an error message when the active electrode surface deviates from specified values.

6. The method according to claim 1, wherein an electrochemically active surface of the electrodes of the sensor is determined by the shape of the electrodes and a dielectric.

7. The method according to claim 1, wherein said first admittance and said second admittance are measured simultaneously.

8. The method according to claim 1, wherein said first admittance and said second admittance are measured successively.

9. The method according to claim 1, wherein said value is a ratio formed between said first and second admittances.

10. The method according to claim 1, wherein said first and second admittances are determined by applying a high-frequency, low-voltage alternating voltage to said electrodes.

11. The method according to claim 1, further comprising,

determining if a parasitic contact resistance is out of a predetermined tolerance.

12. The method according to claim 1, further comprising,

determining if a parasitic contact resistance is out of a predetermined tolerance;

and

displaying an error message when said parasitic contact resistance is out of said predetermined tolerance.

14. A measuring instrument for error checking an electrochemical sensor having at least two electrodes with a liquid measuring medium applied thereto, the instrument comprising:

contacts electrically connecting to the electrodes of the sensor;

electronics generating test voltages and detecting sensor signals from the electrodes;

a processor carrying out the method according to claim 1; and

an output unit providing said error message.

15. A system comprising:

at least one electrochemical sensor with at least two electrodes; and

a measuring instrument for error checking said electrochemical sensor when having a liquid measuring medium applied thereto, said instrument having;

contacts electrically connecting to the electrodes of the sensor,

electronics generating test voltages and detecting sensor signals from the electrodes,

a processor carrying out the method according to claim 1, and

an output unit providing said error message.

13. A method for checking changes in geometry of a detection zone in a measuring chamber of an electrochemical sensor having at least two electrodes, the method comprising:

applying a liquid measuring medium to the electrodes of the electrochemical sensor;

applying an alternating voltage to the electrodes of the electrochemical senor wetted by the measuring medium;

determining a first admittance between a first set of electrodes of the electrochemical sensor wetted by the measuring medium;

determining a second admittance between a second set of electrodes of the electrochemical sensor wetted by the measuring medium;

determining a value forming a ratio between said first admittance and said second admittance; and

assessing the value if the value deviates from a reference state.