Application of micellar electrokinetic capillary chromatography to the analysis of uncharged pesticides of environmental impact

A test mixture of five pesticides and metabolites (naphthalene acetamide, carbaryl, 1-naphthol, thiabendazole, and carbendazime) has been investigated by capillary electrophoresis with an ultraviolet diode array detector. These compounds were separated in <10 min by micellar electrokinetic capillary chromatography (MEKC). MEKC was performed in 30 mM ammonium chloride/ammonia buffer (pH 9.0) containing 15 mM sodium dodecyl sulfate. The lowest detection limit was obtained for the insecticide carbaryl (0.22 microg mL(-)(1)) and the highest for its metabolite 1-naphthol (1.13 microg mL(-)(1)). This method was applied to the analysis of the pesticides in cultivated vegetables such as cucumbers, which were extracted with a liquid-liquid extraction procedure, obtaining recovery percentages ranging from 90.1 to 110.2%.