Separation and determination of pesticides by capillary electrophoresis. I. Rapid separation of fifteenN-methylcarbamate insecticides via micellar electrokinetic chromatography

In this article, micellar electrokinetic chromatography (MEKC) separation of 15 N-methylcarbamate insecticides with a wide span of hydrophobicity was studied. Influences of various buffer parameters such as sodium dodecyl sulfate (SDS) concentration, ionic strength, and modifiers (urea, cyclodextrins) on separation selectivity and analysis time were investigated. Under the optimized running condition (40 mM phosphate with 60 mM SDS and 23 mM hydroxypropyl-β-cyclodextrin, pH 7, voltage 18 kV), satisfactory separation of all 15 analytes was achieved in less than 14 min. Using this new method, residues of carbaryl and its metabolite in a paddy water sample were successfully determined. This new alternative for the separation of N-methylcarbamates is superior to conventional reversed-phase high-performance liquid chromatography (HPLC) approaches in terms of speed of separation and flexibility of selectivity manipulation.