A planar pCO(2) sensor with enhanced electrochemical properties

To develop planar microchemical pCO(2) sensing devices with improved electr ochemical properties, we combined two advanced technologies. One is a diffe rential sensor arrangement to simplify the microfabrication procedure by em ploying pH-sensitive gas-permeable membranes, and the other is the use of a n enzyme (carbonic anhydrase) to shorten total measurement time by accelera ting the rate of CO2 hydration. The adhesion of the polyurethane-matrix gas -permeable membrane is enhanced significantly by incorporating a silanizing reagent (silicon tetrachloride), improving the stability and extending sen sor lifetime. The proposed differential pCO(2) microelectrodes exhibited si gnificantly improved performance in their preconditioning period, response and recovery times, stability, response slope, and lifetime.