A SOLID POLYMER ELECTROLYTE-BASED ETHANOL GAS SENSOR

Platinum-based membrane-electrode assemblies have been prepared to mak e electrochemical measurements of breath alcohol levels. Measurements are made by using a solid polymer electrolyte ethanol-air fuel cell. A diffusion membrane is placed in the feed compartment to limit the cel l response by ethanol diffusion. The cell is found suitable for the re alization of gaseous ethanol sensors. Reproducible cell responses are obtained over several hundreds of cycles. The cell current is proporti onal to the ethanol concentration in the feed compartment and to the t hickness of the diffusion membrane. The transient response of the cell is simulated using Fickian phenomenological equations. Calculated res ults are in good agreement with experimental data.