Development of a Broad-Specificity Immunoassay for Determination of Organophosphorus Pesticides Using Dual-Generic Hapten Antigens

For simultaneously monitoring two classes of organophosphorus pesticide residues in food samples, a polyclonal antibody against a dual-generic hapten immunogen, which was prepared by conjugating two generic haptens (O,O-dimethyl thiophosphate hapten and O,O-diethyl phosphate hapten) to the same carrier protein BSA, was raised and used to develop a broad-specificity competitive indirect enzyme-linked immunosorbent assay. With the optimized conditions, the developed immunoassay was able to detect 11 organothiophosphate pesticide and 5 organophosphate pesticide residues with detection limits of 0.018-0.135 mu g/mL and 0.013-0.171 mu g/mL, respectively. Recoveries of paraoxon-ethyl, fenamiphos, parathion-methyl, and fenthion from spiked samples ranged between 85.8 and 105.5 %. The results indicated that the immunoassay developed in this study is suitable for high-throughput screening of these low-molecular-weight contaminants in food samples.