Development of an enzyme-linked immunosorbent assay for the simultaneous determination of parathion and imidacloprid

A multi-determinant immunogen was prepared by haptens of parathion and imidacloprid conjugated to bovine serum albumin (BSA). The broad-specificity polyclonal antibody (BsPAb) was generated by male New Zealand white rabbits immunized with the multi-determinant immunogen. The antibody was screened against six different coating antigens. An indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) was developed and used for the analysis of parathion and imidacloprid simultaneously. Under the optimized conditions, the 50% inhibition concentration (IC50) value for parathion and imidacloprid was 0.052 and 1.70 mg L−1, with a limit of detection (LOD, IC10) of 0.0005 and 0.0045 mg L−1, respectively. There was no obvious cross-reactivity (CR) with most of the neonicotinoids and organophosphorus insecticides, except for imidaclothiz (23.9%) and acetamiprid (6.17%). The recoveries of parathion and imidacloprid in environmental and agricultural samples, including tap water, river water, soil and cabbage, ranged from 87.2% to 117% and 84.4% to 107%, respectively. These results showed that the ic-ELISA can be used as a sensitive tool for detecting parathion and imidacloprid simultaneously in environmental and agricultural samples.