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Electrophoretic concentration and sweeping-micellar electrokinetic chromatography analysis of cationic drugs in water samples A

Wuethrich, Alain, Haddad, Paul R., Quirino, Joselito P.
Journal of chromatography 2015 v.1401 pp. 84-88
acetonitrile, ammonium acetate, chromatography, detection limit, drugs, electric power, electrolytes, electrophoresis, pH, sodium dodecyl sulfate, sodium phosphate, wastewater
Sample preparation by electrophoretic concentration, followed by analysis using sweeping-micellar electrokinetic chromatography, was studied as a green and simple analytical strategy for the trace analysis of cationic drugs in water samples. Electrophoretic concentration was conducted using 50mmol/L ammonium acetate at pH 5 as acceptor electrolyte. Electrophoretic concentration was performed at 1.0kV for 50min and 0.5kV and 15min for purified and 10-fold diluted waste water samples, respectively. Sweeping-micellar electrokinetic chromatography was with 100mmol/L sodium phosphate at pH 2, 100mmol/L sodium dodecyl sulfate and 27.5%-v/v acetonitrile as separation electrolyte. The separation voltage was −20kV, UV-detection was at 200nm, and the acidified concentrate was injected for 36s at 1bar (or 72% of the total capillary length, 60cm). Both purified water and 10-fold diluted waste water exhibited a linear range of two orders of concentration magnitude. The coefficient of determination, and intra- and interday repeatability were 0.991–0.997, 2.5–6.2, and 4.4–9.7%RSD (n=6), respectively, for purified water. The values were 0.991–0.997, 3.4–7.1, and 8.7–9.8%RSD (n=6), correspondingly, for 10-fold diluted waste water. The method detection limit was in the range from 0.04–0.09 to 1.20–6.97ng/mL for purified and undiluted waste water, respectively.