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 investigated in alkaline solutions using cyclic voltammetry and the modulated potential-time waveform (MPTW) technique. It was found that suitable MPTWs can produce reproducible results after the elimination of the absorbed ''poison'' formed during glucose oxidation, leaving a clean electrode surface. The effects of the experimental conditions on the voltammetric characteristics of glucose oxidation were studied systematically. These results were explained by an oxidation mechanism via the rate-determining decomposition of adsorbed glucose with the release of a hydrogen 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 surface. By making use of Nafion(R)-modified Pt electrodes, it was found that the interference of several biologically active small organic molecules, such as ascorbic acid, cysteine and uric acid, with the oxidation of glucose was suppressed effectively, forming the basis for studies of practical electrochemical sensors.