POST-ION-CHROMATOGRAPHY DERIVATIZATION FOR THE DETERMINATION OF OXYHALIDES AT SUB-PPB LEVELS IN DRINKING-WATER

A new ion chromatographic method is presented that successfully determ ines iodate, chlorite, and bromate in drinking water at practical quan titation limits of 0.1, 0.4, and 0.2 mu g/L, respectively. Sample pret reatment is not required, The sensitivity of detection is enhanced by conversion of the eluting oxyhalides into the tribromide ion by a post column reaction with bromide under acidic conditions, Spectrophotometr ic detection of the tribromide ion is at 267 nm, Optimization of the r eaction conditions was studied, and the effective operating parameters are presented, The method detected significant levels of bromate in b ottled water as well as low levels of iodate in tap water, All results were quality assured, and spike recoveries were in the range 94-110%, The method is applicable to a wide range of waters containing high le vels of ions and organic carbon.