Determination of pyrethroid pesticide residues in vegetables by pressurized capillary electrochromatography

A simple and rapid pressurized isocratic capillary electrochromatography (pCEC) method has been developed to separate six pyrethroid pesticides. The effects of pH of buffer, organic solvent content, buffer concentrations and applied voltage on the separation of six pyrethroids were investigated. Under the optimized conditions, the pCEC method developed allows baseline separation of a complex mixture of six pyrethroids in <20 min. The method is applied to the analysis of these pesticide residues in Chinese cabbage. The limits of quantification (LOQ) ranged from 0.5 to 0.8 microg/ml (corresponding to 0.05 and 0.08 mg/kg in the vegetable sample), with relative standard deviations (R.S.D.) <5.0%. Mean values of recoveries for six pyrethroids ranged from 89.6 to 96.3%, respectively.