The Rate of Oxidation of Dimethylarsinous Acid to Dimethylarsinic Acid is Ph Dependent: Implications for the Analysis and Toxicology of Arsenic Metabolites in Urine

Abstract

A ¹H NMR spectroscopic study has shown the rate oxidation of dimethylarsinous acid to dimethylarsinic acid in buffered aqueous solutions to depend upon pH. Dimethylarsinous acid has been reported to be a highly toxic arsenical metabolite and component of the urine of persons exposed to inorganic arsenic, particularly through drinking water. As the pH of human urine can range from 4.5 to 8, the pH dependence of the oxidation rate of dimethylarsinous acid to dimethylarsinic acid has profound implications for the detection and analysis of these compounds in urine samples, and for the relevance of the experimental toxicology of dimethylarsinous acid.