DETERMINATION OF CHLORITE AND CHLORATE IN CHLORINATED AND CHLORAMINATED DRINKING-WATER BY FLOW-INJECTION ANALYSIS AND ION CHROMATOGRAPHY

This research investigated the determination of chlorite and chlorate concentrations in drinking water by flow injection analysis (FIA) with iodometric detection and ion chromatography (IC) with conductivity detection. The FIA and IC methods were accurate and effective for reagent water. The IC method was accurate for measurement of chlorite and chlorate concentration in drinking water even in the presence of other oxidants including chloramines. However, FIA was affected by chloramines and other oxidants in drinking water, resulting in inaccurate determinations. While chlorite concentrations were unstable in chlorinated drinking water, addition of sodium oxalate increased the stability to up to 3 days and addition of ethylenediamine increased stability to up to 18 days. Chlorate concentration were stable in drinking water for up to 18 days with or without a preservative.