Simple spectrophotometric determination of sulfate free radicals

A rapid, simple, and sensitive spectrophotometric method for sulfate radical determination in aqueous solutions was developed, employing the reaction between sulfate radicals and cerium(III) sulfate to quantitatively generate cerium(IV) sulfate. The relative concentrations of sulfate radicals were evaluated through Ce4+ quantitation by UV-spectrophotometry. Factors affecting this method, including the concentration of cerium sulfate concentration, reaction time, pH, and inorganic anions, were investigated. Finally, using this method, the rate of sulfate radical generation by photolysis of peroxydisulfate under different light sources was studied.