Anodic oxidation of carbohydrates and their derivatives in neutral saline solution.

Abstract

Rao and Drake1 have recently reported work on the oxidation of dextrose on platinized platinum in neutral buffer solution (pH 7.4). They have shown that anodic charging curves on platinized platinum electrodes in 0.5 M dextrose solution go through an inflexion at about 0.1 V referred to standard hydrogen electrode (SHE) (where platinum starts to adsorb oxygen in neutral solution), after which oxidation is inhibited. No square root dependence was noted for the transition time to this point, indicating that the inhibitive process was not under diffusion control. In addition, the total number of coulombs required to reach the point of inflexion decreased if increasing concentrations of gluconic acid were added to the dextrose solution. They reported open circuit potential (OCP) of + 0.3 V (SHE) in deaerated gluconic acid solution (10−4 to 10−1 M), and they detected no evidence of gluconic acid oxidation in the potential range −0.6 to 0.0 V (SHE). Their general conclusions were that the only oxidation product of glucose in these conditions is gluconic acid, which adsorbs on the electrode in the potential range −0.2 to 0.0 V (SHE), effectively inhibiting glucose oxidation.