Simultaneous Determination of Florfenicol and Its Metabolite Florfenicol Amine in Swine Muscle Tissue by a Heterologous Enzyme-Linked Immunosorbent Assay

Abstract

A sensitive and heterologous enzyme-linked immunosorbent assay (ELISA) for the simultaneous detection of florfenicol (FF) and its metabolite florfenicol amine (FFA) in swine muscle tissue was developed. FFA was conjugated to bovine serum albumin by a formaldehyde coupling method as an immunogen to immunize rabbits. FFA, thiamphenicol glycinate, and modified FF were conjugated to ovalbumin as coating antigens. The effect of different types of hapten heterology on the sensitivity and specificity of the ELISA was evaluated. Using FF glutaric anhydride ester as a coating hapten and antibody raised against modified FFA, an ELISA was developed that showed an IC50 value of 0.48 ng/mL. The antibody showed a cross-reactivity of 100% with FFA, 97% with FF, 6% with thiamphenicol, and a negligible value with chloramphenicol. From fortified swine muscle samples at levels of 4-320 ng/g, the average recoveries of FF and FFA ranged from 58.2 to 96.8%, with coefficients of variation less than 14%. Analysis of incurred samples by the ELISA gave similar results to those by a previously developed liquid chromatographic method. The ELISA could be used as a rapid method for the simultaneous determination of FF and FFA in swine muscle tissue.