Simultaneous HPLC Determination of Peroxyacetic Acid and Hydrogen Peroxide

The first instrumental method for simultaneous determination of peroxyacetic acid (PAA) and hydrogen peroxide has been developed. The successive quantitative reaction of PAA with methyl p-tolyl sulfide (MTS) and hydrogen peroxide with triphenylphosphine (TPP) yields the corresponding sulfoxide MTSO and phosphine oxide TPPO. The reagents and their oxides are separated by HPLC on reversed-phase columns with acetonitrile/water gradient elution within 5 min. External calibration with the solid standards of MTSO and TPPO leads to a very accurate and reliable method. Samples are stable and can be stored after derivatization for several days prior to analysis. Real samples from brewery disinfection were analyzed in comparison to titration with excellent correlation.