All-Solid-State Glucose Sensor Using Proton-Conductive Thick Film

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Abstract
A solid-state glucose sensor using a proton-conductor thick film was investigated as a possible approach to a miniaturized enzyme sensor. A planar-type electrochemical cell, (reference electrode) Au|antimonic-acid thick film (proton conductor)|Pt-GOD (sensing electrode), was fabricated on a porous alumina substrate. When measured in a phosphate buffer solution of pH 7.0 at 30°C, the emf of the sensor varied logarithmically with a change in glucose concentration in the range from 5×10-4 to 4×10-2 M, following a Nernst equation. The 90% response time was about 1 min. The glucose sensitivity was fairly stable for 10 days. The Nernst slope (-54 mV/decade) was very close to that (-55 mV/decade) of the responses to H2O2, indicating that the glucose-sensing signal was generated by responding to the H2O2 produced by the enzymatic reaction of glucose.