Analysis of carbofuran, carbosulfan, isoprocarb, 3-hydroxycarbofuran, and 3-ketocarbofuran by micellar electrokinetic chromatography

We developed an analytical method for the detection and quantitation of five pesticides and some of their metabolites - 3-hydroxycarbofuran, 3-ketocarbofuran, carbofuran, carbosulfan, and isoprocarb - using micellar electrokinetic chromatography coupled with a UV-Vis detector. The optimum separation conditions were 20 mM phosphate buffer (pH 8.0) containing 15 mM sodium dodecyl sulfate. The detection wavelength was set at 200 nm and the applied voltage was 12.5 kV. Under these conditions, baseline separation of five pesticides was achieved in 15 min, and the detection limits (S/N = 3) of 3-hydroxycarbofuran, 3-ketocarbofuran, carbofuran, carbosulfan, and isoprocarb were 0.3, 0.3, 0.3, 4.0, and 0.3 μM, respectively. The linear ranges for 3-hydroxycarbofuran, 3-ketocarbofuran, carbofuran, and isoprocarb were between 1.0 and 50.0 μM and that for carbosulfan was between 10.0 and 100.0 μM, with R(2) larger than 0.995. When applied to the analysis of a carbofuran-spiked rice sample, this approach yielded results with excellent repeatability (3.3%, n = 5), reproducibility (4.5%, n = 5), separation efficiency (>2.1 × 10(4) theoretical plates), and recovery (95.5 ± 1.4%, n = 5).