Simultaneous quantification of peracetic acid and hydrogen peroxide in different water matrices using HPLC-UV

With low potential to generate harmful by-products, peracetic acid (PAA) has drawn increasing attention as an alternative oxidant for disinfection and advanced oxidation processes in wastewater treatment. Commercial formulations contain significant concentrations of both PAA and H2O2 in aqueous solutions and a robust method to distinctively quantify the two respective oxidants simultaneously is needed. This study aimed to improve the accuracy of employing methyl p-tolyl sulfide (MTS) and triphenylphosphine (TPP) as indicators for PAA and H2O2, respectively, under various environmental conditions, by the detection of the oxidation products of sulfoxide MTSO and phosphine oxide TPPO using HPLC-UV. To improve the analytical method, the reaction rates of MTS and TPP with PAA and H2O2, impact of pH on the detection, and matrix effects of real wastewater effluents and produce wash water were evaluated to minimize the interference of H2O2 with PAA determination. The determined rate constants of PAA reaction with MTS (kPAA/MTS=34.6±0.4M−1s−1 in 2/1 H2O/acetonitrile (ACN) (v/v)) and H2O2 reaction with TPP (kH2O2/TPP=2.7±0.2M−1s−1 in 1/1 H2O/ACN (v/v)) provided the fundamental guidance to optimize the method. Overall, a highly accurate and sensitive method for simultaneous quantification of PAA and H2O2 (method quantification limit = 0.8 and 6.0 μM, respectively) is established and will be useful for various environmental samples with PAA and H2O2 applications.