Development of a broad-spectrum monoclonal antibody-based indirect competitive enzyme-linked immunosorbent assay for the multi-residue detection of avermectins in edible animal tissues and milk.

Avermectins (AVMs) are a group of anti-parasitic agents that have been widely used in food-producing animals. To monitor the residue of the AVMs, an indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) was developed with a simple sample preparation procedure. Conjugates of 4″-HS-IVM/AVM on three different proteins were used to raise a broad-spectrum monoclonal antibody (mAb), 6D4, that had IC values for avermectin, ivermectin, eprinomectin and emamectin of 7.2, 10.4, 19.8 and 20.8 µg L, respectively. The limit of detection and limit of quantitation of this method for AVMs in various matrix samples ranged from 0.5 to 5.4 µg L and 1.0 to 10.3 µg L, respectively. The recoveries of the samples spiked with AVMs were in the range of 78.1-110.5% with coefficients of variation below 14%. The ic-ELISA was applied to monitor ivermectin in the milk samples, and the results showed a good correlation with that of HPLC-MS/MS.