Polarographic Studies of Dissolved Oxygen in DMSO-Water Mixtures

Abstract

The solubility and polarographic behavior of dissolved oxygen have been investigated in air-saturated DMSO-water mixtures at 25°C and 45°C. The first oxygen wave, which corresponds to one-electron reduction to superoxide ions in water-poor DMSO solutions of 0.1 m Et4NClO4, changes to a two-electron process in the range of water content between 10 and 30% because of the protonation reaction due to water. The rate of protonation is potential-dependent. The rate also depends on the species and the concentrations of the supporting electrolytes. The temperature effect is small. Using the solubility and polarographic data obtained, the polarographic diffusion coefficients of oxygen in the mixed solvent have been calculated.