ELECTROOXIDATION OF GLUCOSE ON PLATINUM IN ALKALINE-SOLUTION AND SELECTIVE OXIDATION IN THE PRESENCE OF ADDITIVES

The electrochemical behavior of glucose at Pt electrodes was investiga ted in alkaline solutions using cyclic voltammetry and the modulated p otential-time waveform (MPTW) technique. It was found that suitable MP TWs can produce reproducible results after the elimination of the abso rbed ''poison'' formed during glucose oxidation, leaving a clean elect rode surface. The effects of the experimental conditions on the voltam metric characteristics of glucose oxidation were studied systematicall y. These results were explained by an oxidation mechanism via the rate -determining decomposition of adsorbed glucose with the release of a h ydrogen atom. The applicability of MPTW amperometry and coulometry to the measurement of glucose concentration was demonstrated. Glucose can penetrate the Nafion(R) membrane which modifies the Pt electrode surf ace. By making use of Nafion(R)-modified Pt electrodes, it was found t hat the interference of several biologically active small organic mole cules, such as ascorbic acid, cysteine and uric acid, with the oxidati on of glucose was suppressed effectively, forming the basis for studie s of practical electrochemical sensors.