Sensor interrogation

1. A method of testing a system having at least one electrochemical sensor for detecting an analyte gas within a housing of the system and a secondary sensor within the housing for detecting a change in concentration of a chemical species other than the analyte, the housing of the system having an inlet, comprising:

creating a driving force other than by application of the analyte gas or a simulant gas in the vicinity of the inlet of the housing of the system to cause a change in the concentration of the chemical species other than the analyte; and

measuring change in the concentration of the chemical species other than the anal caused by the driving force to test one or more transport paths of the system.

2. The method of claim 1 wherein creating the driving force comprises exhaling in the vicinity of the inlet of the housing.

3. The method of claim 1 wherein the secondary sensor is responsive to carbon dioxide.

4. The method of claim 1 wherein the secondary sensor is responsive to oxygen.

5. The method of claim 1 further comprising:

simulating the presence of the analyte gas electronically; and

measuring a response of the electrochemical sensor to the electronic simulation.

6. The method of claim 5 wherein a constant current is caused to flow between a first working electrode and a counter electrode of the electrochemical sensor and the measured response is a potential difference.

7. The method of claim 5 wherein a constant potential difference is maintained between a first working electrode and a counter electrode of the electrochemical sensor and the measured response is a current.

8. The method of claim 5 wherein the electrochemical sensor is an amperometric sensor.

9. The method of claim 5 wherein the electrochemical sensor comprises a first working electrode responsive to the analyte gas and a second working electrode responsive to a gas within exhaled breath.

10. The method of claim 9 wherein the electrochemical sensor comprises a sensor housing comprising at least one inlet into an interior of the sensor housing, the first working electrode and the second working electrode being positioned within the sensor housing.

11. The method of claim 10 wherein each of the first working electrode and the second working electrode independently comprises an eletrocatalytically active material deposited upon a porous membrane through which gas can diffuse.

12. The method of claim 1 wherein the electrochemically active electrode comprises a wire or a ribbon.

13. The method of claim 12 wherein the wire or the ribbon comprises an eletrocatalytically active material deposited thereon.

14. The method of claim 12 wherein the electrochemically active electrode comprises a section of increased surface area per unit length in operative connection with the wire or the ribbon.

15. A method of testing a system, including a system housing, at least one inlet formed in the system housing, at least one electrochemical sensor for detecting an analyte gas within the system housing, at least one sensor responsive to the presence of exhaled breath within the system housing and one or more porous diffusion barriers through which gas diffuses but through which liquid has limited mobility, the at least one electrochemical sensor and the at least one sensor responsive to the presence of exhaled breath being positioned within the system housing so that the one or more porous diffusion barriers are between an environment outside of the inlet and the at least one electrochemical sensor, the method comprising:

exhaling in the vicinity of the inlet of the system housing; and

measuring a response of the sensor responsive to the presence of exhaled breath to test one or more transport paths of the system between the inlet of the system housing and the at least one electrochemical sensor including a transport path through each of the one or more diffusion barriers.

16. A system for detecting at least one analyte gas, comprising:

a system housing comprising an inlet system;

one or more porous diffusion barriers though which gas diffuses but through which liquid has limited mobility;

an electrochemical gas sensor within the housing and in fluid connection with the inlet system through each of the one or more porous diffusion barriers, the electrochemical sensor being responsive to the at least one analyte gas, and

at least one other sensor within the housing and in fluid connection with the inlet system through each of the one or more porous diffusion barriers, the at least one other sensor being responsive to at least one driving force created in the vicinity of the inlet system other than by application of the at least one analyte gas or a simulant gas to which the electrochemical sensor is responsive to provide an indication of a state of a transport path between the inlet system and the electrochemical gas sensor, including a transport path through each of the one or more porous diffusion barriers.

17. The system of claim 16 further comprising:

a power source in electrical connection with the electrochemical gas sensor to simulate the presence of the analyte gas electronically; and

circuitry to measure a response of the electrochemical gas sensor to the electronic simulation.

18. The system of claim 17 wherein the at least one other sensor comprises an electrochemically active electrode responsive to the at least one driving force.

19. The system of claim 17 wherein the power source is adapted to cause a current to flow between a first working electrode and a counter electrode of the electrochemical gas sensor and the measured response is a potential difference.

20. The system of claim 17 wherein the power source is adapted to maintain a potential difference between a first working electrode and a counter electrode of the electrochemical gas sensor and the measured response is a current.