Simultaneous Determination of Three Trace Organophosphorus Pesticide Residues in Vegetables Using Molecularly Imprinted Solid-Phase Extraction Coupled with High-Performance Liquid Chromatography

In this study, a molecularly imprinted polymer that can selectively recognize dimethoate, isocarbophos, and methyl parathion was synthesized. Using this compound as sorbent, a new method for simultaneous determination of the three organophosphorus pesticides by molecularly imprinted solid-phase extraction coupled with high-performance liquid chromatography was established. The factors affecting the preconcentration and sensitivity were studied in detail. Under optimal conditions, the limits of detection of this method for dimethoate, isocarbophos, and methyl parathion were 19.78, 8.73, and 17.41 mu g/kg, respectively. The relative standard deviation for five replicates of 0.01 mg/L-mixed solutions was in the range of 1.8-4.2 %. Cucumber sample spiked with the three organophosphorus pesticides at levels of 0.125 and 0.250 mu g/g were examined using this method, good recoveries were obtained ranging from 82.5 to 95.6 %. Moreover, this method was also successfully used for the detection of the three organophosphorus pesticides in cauliflower sample.