Determination of rotenone in river water utilizing packed capillary column switching liquid chromatography with UV and time-of-flight mass spectrometric detection

Fast and sensitive packed capillary column switching liquid chromatography methodology has been developed for the determination of the pesticide rotenone in river water. Sample volumes of up to 1 ml are loaded onto a 23 X 0.25 mm, 5 mum Kromasil C-18 packed capillary precolumn using a noneluting solvent composition of water-acetonitrile (99:1, v/v) at flow-rates up to 100 mul/min prior to solute backflushing onto a 200X0.32 mm, 3.5 mum Kromasil C-18 packed capillary analytical column using a mobile phase of water-acetonitrile (30:70, v/v) at a flow-rate of 5 mul/min. The method was evaluated using river water samples spiked with rotenone in the concentration range 0.5-50 ng/ml using UV detection. The within-assay precision was between 5.0 and 7.7% relative standard deviation (RSD, n=6) and the between assay precision was between 7.5 and 8.9% RSD (n=6). The method was linear within the investigated mass range displaying a calibration curve correlation factor of 0.997. The mass limit of detection was 10 pg corresponding to a concentration limit of detection of 10 pg/ml, using time-of-flight mass spectrometry. (C) 2002 Elsevier Science B.V. All rights reserved.