Patent ID: 6663756
Filing Date: 2003-12-16
Classification: G01N

Abstract:
A microchip-based differential oxygen gas sensor comprising a working electrode and a reference electrode, whereina) the working electrode comprises a cobalt-plated electrode 13 on a Agâ€”Pt layer, a buffered hydrogel layer 14, and an ion-selective gas-permeable membrane; and b) the reference electrode comprises a Ag/AgCl electrode 12 on a Agâ€”Pt layer, which is non-selective to oxygen gas, a buffered hydrogel layer, which is made of the same material as the buffered hydrogel layer of the working electrode, and an ion-selective gas-permeable membrane, which is made of the same material as the ion-selective gas-permeable membrane of the working electrode, wherein the buffered hydrogel layer comprises a buffer solution containing 2-5 mM of sodium chloride or potassium chloride, and 2-7% by weight of a hygroscopic material.