Development of a monoclonal antibody-based indirect competitive enzyme-linked immunosorbent assay for screening of diethylstilbestrol in animal-derived foods

Diethylstilbestrol (DES), a synthetic non-steroid estrogen, it has been prohibited from being added to animal feed for any purposes. Herein, an indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) based on a specific monoclonal antibody (mAb) was developed for the rapid screening of DES. Primarily, conjugates of mono-O-3-carboxypropyl diethylstilbestrol with keyhole limpet hemocyanin were used to raise a specific mAb, 1B7, which had IC₅₀ value for DES of 213.0 ng L^-1. The limits of detection and limits of quantification value for DES in animal-derived foods ranged from 68.1 to 103.1 ng L^-1 and 100.8-192.7 ng L^-1, respectively. The DES recovery ranged from 70.1 % to 103.1 %, with coefficients of variation below 13.9 %. A positive correlation (R² = 0.997) was observed between the results of ic-ELISA and HPLC-MS/MS for milk. In order to inspect its detection effect, milk and animal-derived foods were chosen as the testing object. The results showed that this ic-ELISA method (specific mAb, 1B7) can effectively examine for DES residues.