Broad specific enzyme-linked immunosorbent assay for determination of residual phenothiazine drugs in swine tissues

In this study, a novel generic hapten of phenothiazine drugs was synthesized by derivatization of 2-chlorophenothiazine with sodium bromoacetate. Then the hapten was coupled to bovine serum albumin for production of the monoclonal antibody. Results showed that the obtained monoclonal antibody recognized five phenothiazine drugs simultaneously: chlorpromazine, promethazine, acepromazine, perphenazine, and fluphenazine. After evaluation of different coating antigens, a heterologous competitive indirect enzyme-linked immunosorbent assay was developed to determine the residues of the five phenothiazine drugs in swine tissues (muscle, liver, and kidney). The cross-reactivities to the five analytes were in the range of 71 to 98%, and the limits of detection were in the range of 0.2 to 0.4 ng/ml, depending on the drug. Their recoveries from the fortified blank samples were in the range of 73.8 to 96.2%, with coefficients of variation in the range of 4.1 to 14.3%. This is the first study reporting a broad specific immunoassay for multi-determination of the residues of five phenothiazine drugs in animal-derived foods.