Development Of Enzyme-Linked Immunosorbent Assay For The Determination Of Phosmet Residues

In this study,a panel of phosmet haptens was synthesized for immunoconjugate preparation,several haptens for heterologous tracer conjugates were also prepared.A highly sensitive polyclonal antibody against the organophosphorus(OP) insecticide phosmet was obtained and competitive direct enzyme-linked immunosorbent assays (cd-ELISA) for this pesticide were developed.In the cd-ELISA,the limit of detection(IC₁₅) was 0.6μg/kg±0.016μg/kg,and the sensitivity(IC₅₀) was 20μg/kg±0.20μg/kg.The suitability of the ELISA for pesticide quantification in various food samples was also studied,including solid and liquid samples:peach,apple,cabbage,cucumber,orange juice and apple juice.Phosmet was quantitied by simple extraction and dilution using PBS without any concentration or cleanup steps.With a lower limit and more convenient pre-treatment,the cd-ELISA test successfully quantitated phosmet in food samples far below their MRL.Good accuracy and precision were obtained with mean recoveries between 78%and 102.3%,and mean coefficients of below 13.63%.Validation of the ELISA was conducted by high-performance liquid chromatography. The correlation between the data obtained using the microwell assay and the HPLC was good(R²=0.9849).The developed immunoassay methods were suitable for the rapid quantitative or qualitative determination of phosmet in food samples.