The use of nitrite ion in the chromatographic determination of large amounts of hypochlorite ion and of traces of chlorite and chlorate ions

An ion chromatographic procedure was developed for the one-run determinatio n of ClO-, ClO2- and ClO3- present at very different concentration levels i n the same sample. The method is based on the quantitative and fast reducti on of HClO in slightly acidic medium by added sodium nitrite, followed by t he ion chromatographic determination of ClO2-, ClO3- and the generated NO3- . The possibility of amperometric titration of the 'free chlorine' with a s tandard solution of NaNO2 was also ascertained. The performance characteris tics of the analysis were defined.