Simultaneous Tracking of Sulfur Species in the Oxidation of Thiourea by Hydrogen Peroxide

We employ reversed-phase ion-pair high-performance liquid chromatography to quantitatively characterize the oxidation kinetics of thiourea oxidation by hydrogen peroxide. The HPLC technique makes it possible to monitor the concentrations of a variety of sulfur-containing species with different oxidation states and to elucidate the relative phase relations among them. The experimental results are in good agreement with simulations from an 8-step reaction mechanism. Oxidation reactions of sulfur(-II) compounds such as thiourea (TU) can be quite complex, yielding species with oxidation states ranging from-1 to +6.1–4 Researchers have investigated the dynamics of these reactions from several perspectives: First, the mechanism of the nonlinear reaction between various oxidants and TU is of considerable interest for explaining such exotic phenomena as oscillations, chaos and spatiotemporal patterning seen in such systems.5–8 Secondly, the physiological effects of thiourea oxides have attracted scientists to explore the biofunction of these sulfur species.9,1