Determination of chlorite in drinking water by on-line coupling of capillary isotachophoresis and capillary zone electrophoresis

An isotachophoresis (ITP)–capillary zone electrophoresis (CZE) combination was used for the determination of chlorite in drinking waters. No sample preparation is needed and no interfering by other anions in tap water was observed. The reached limits of detection with conductivity detector were 0.012–0.017 mg l−1. By four-fold sample loading with a 30 μl valve, 0.005 mg l−1 of chlorite was determined with R.S.D.=3.3%. The concentrations of 0.05 and 0.20 mg l−1 were measured with R.S.D. of 2.2 and 2.7%, respectively. The recoveries of chlorite from drinking water were 96–106% in the range of 0.02–0.20 mg l−1. The R.S.D. values of migration times (inter-day) were up to 1.3%. The time for analysis is about 15 min.