Preparation of a generic monoclonal antibody and development of a highly sensitive indirect competitive ELISA for the detection of phenothiazines in animal feed.

In this study, a broadly specific monoclonal antibody was prepared and a sensitive monoclonal-based indirect competitive enzyme linked immunosorbent assay (ic-ELISA) was subsequently developed to determine the phenothiazines in animal feed with a simple sample preparation procedure for the first time. The obtained antibody 3A5 was of the immunoglobulin G1 (IgG1) isotype possessing a kappa light chain, which broadly cross-reacted to nine phenothiazines. The limit of detections of the method ranged from 1.1μgkg-1 to 15.3μgkg-1 in the swine feed and the fish feed. The recoveries of the phenothiazines were in the range of 78.2-116.6%. The coefficient of variations were less than 16.7%. A positive correlation (r>0.9249) between the results of the ic-ELISA and the high-performance liquid chromatography were also observed, which indicated that the developed ic-ELISA is reliable and can be used to monitor phenothiazines in animal feed.