Development of a Direct Competitive Biomimetic Enzyme-Linked Immunosorbent Assay Based on a Hydrophilic Molecularly Imprinted Membrane for the Determination of Trichlorfon Residues in Vegetables

In recent years, there has been an increasing demand on the determination of trace trichlorfon residues in fresh vegetables. In this study, a sensitive direct competitive biomimetic enzyme-linked immunosorbent assay (BELISA) method was developed for the determination of trichlorfon based on a hydrophilic imprinted membrane, which was directly synthesized on the well surface of MaxiSorp polystyrene 96-well plate through bulk polymerization technology. This novel imprinted membrane was characterized with high binding ability and specificity. Under the optimal conditions, the sensitivity (IC 50 , half maximal inhibitory concentration) and the limit of detection (LOD, IC 15 ) of this method were 6800 ± 60 μg/L and 6.8 ± 0.20 μg/L, respectively. This BELISA method had been applied to the determination of trichlorfon with good recoveries ranging from 106.0 to 110.5%, and the results were correlated with that obtained by the gas chromatography method. Moreover, this method was applied to quantitative detection of trichlorfon residues in the leek samples.