Determination of carbamate pesticides using micellar liquid chromatography

1417-1422Carbaryl, methiocarb and propoxur, have been rapidly determined by micellar liquid chromatography, using a C18 (250×4.0 mm) column, UV-detection (230 nm) and direct injection of the samples. Sodium dodecyl sulphate (SOS), due to its shorter retention times compared to that of Brij-35, and pentanol have been chosen as surfactant and organic modifier respectively in the optimisation procedure. An interpretative optimization strategy has been used to select the optimum mobile phase, SDS 150 mM-6% (v/v) pentanol-pH 3. The analysis time is lower than 10 min. Intra and inter-day precisions are lower than 1.9% in terms of relative standard deviation. Limits of detection (3s criterion) are 0.1 ng mL-1 for carbaryl and 0.6 ng/mL for methiocarb and propoxur. Calibration is linear between the LOD and 100μg mL-1. The developed method has been applied to the determination of carbamates in spiked water samples (domestic tap, agricultural and waste water) at 50 ng mL-1 concentration levels. The results are similar to those obtained by the Environmental Protection Agency (EPA) reference method