A Facile, Nonreactive Hydrogen Peroxide (H2O2) Detection Method Enabled by Ion Chromatography with UV Detector.

Hydrogen peroxide (H2O2) is ubiquitous in the natural environment, and it is now widely used for pollutant control in water and wastewater treatment processes. However, current analytical methods for H2O2 inevitably require reactions between H2O2 and other reactants to yield signals and are thus likely subjective to the interferences of coexisting colored, oxidative, and reductive compounds. In order to overcome these barriers, we herein for the first time propose to analyze H2O2 by ion chromatography (IC) using an ultraviolet (UV) detector. The proposal is based on two principles: first, that H2O2 can deprotonate to hydroperoxyl ion (HO2-) when eluent pH is higher than the acid-dissociation coefficient of H2O2 (pKa = 11.6); and second, that after separation from other compounds via IC column, H2O2 can be quantified by a UV detector. Under favorable operating conditions, this method has successfully achieved acceptable recoveries (>91%) of H2O2 dosed to ultrapure and natural waters, a calibration curve with R2 > 0.99 for a wide range of H2O2 concentrations from 0.1 to 50 mg/L and a method detection limit of 0.027 mg/L. In addition, this approach was shown to be capable of distinguishing H2O2 from anions (e.g., fluoride and chloride) and organics (e.g., glycolate) and monochloramine, suggesting that it is insensitive to many neighboring compounds as long as they do not react quickly with H2O2. Hence, this study proves the combination of IC and UV detector a facile and reliable method for H2O2 measurement.