Monitoring of organophosphorus pesticides in vegetables using monoclonal antibody-based direct competitive ELISA followed by HPLC–MS/MS

A multi-analytes method for monitoring of organophosphorus pesticides (OPs) using a combination of broad-specificity direct competitive enzyme-linked immunosorbent assay (dcELISA) and high-performance liquid chromatography–tandem mass spectrometry (HPLC–MS/MS) was developed. The reaction formats of dcELISA as well as the matrix effects of vegetable samples by different treatments were studied. The dcELSIA based on horseradish peroxidase-labelled monoclonal antibody and solid-phase extraction can analyse 42 samples in duplicate simultaneously for 12 OPs with a limit of detection at 20 μg L−1 within 40 min, with good accuracy and reproducibility. For screening purpose, the dcELISA can distinguish positive samples from hundreds of negative samples at a rapid, high-throughput and low cost manner. The positive samples can be following confirmed by HPLC–MS/MS for the kinds and the relative amounts of OPs. The method is suitable for monitoring of OP contamination in vegetables samples with high-efficiency and low cost.