APPLICATION OF CAPILLARY ELECTROPHORESIS IN THE QUALITY-CONTROL OF OSMOTICALLY TREATED WATER

This paper discusses the use of capillary zone electrophoresis (CZE) w ith indirect UV detection for the separation and detection of ions. By use of a 70 cm x 75 mu m i.d. capillary at -15 kV and an electrophore tic buffer containing sodium chromate, l-butanol, and cetyltrimethylam monium bromide as electroosmotic-flow modifier (pH 8) nine inorganic a nd organic anions were separated in less than 10 min. By use of the sa me type of capillary at 20 kV and an electrophoretic buffer containing imidazole and 18-crown-6 (pH 5) eight cations were separated in less than 5 min. The different variables that affect the separation were st udied and optimized; the compounds were detected at low mg L-1 levels after hydrodynamic injection under pressure. The method was tested wit h osmotically treated waters, and the results compared with those obta ined by ion chromatography for anion analysis and by atomic absorption spectroscopy for cation analysis.