Measurement of nitrate and chlorate in swimming pool water by capillary zone electrophoresis

Abstract

Capillary zone electrophoresis (CZE) of nitrate and chlorate in swimming pool water are described. Nitrate and chlorate were determined simultaneously with an indirect detection method in an electrolyte containing 10 mM chromate and 0.1 mM cetyltrimethylammonium bromide (CTAB). Where chloride concentration was so high that nitrate could not be determined satisfactorily because of interference, a direct detection technology was developed in which 10 mM sulfate and 0.1 mM CTAB were used as the buffer. The wavelength for indirect detection was 254 nm and 214 nm for direct detection. Relative standard deviations of the quantification of nitrate and chlorate in real samples were below 6%. The detection limits were 7 μg ml −1 for chlorate, and 4 μg ml −1 (indirect detection) and 0.4 μg ml −1 (direct detection) for nitrate.