Rapid determination of six fluoroquinolones in aquatic product by direct competitive enzyme-linked immunosorbent assay

In this study, a direct competitive enzyme-linked immunosorbent assay (dcELISA) was developed for rapid determination six fluoroquinolones in aquatic product. Horseradish peroxidase-labelled ciprofloxacin monoclonal antibody ( MAb-CIP-HRP) was synthesized by NaIO4method. The effect of coating antigen concentration, competitive reaction time and organic solvents on the sensitivity of dcELISA were investigated.Under the optimized assay conditions, the dcELISA showed the limit of detection below 0.5ng/mL for ciprofloxacin, enrofloxacin, norfloxacin, pefloxacin, sarafloxacin and difloxacin, and the linear range (IC20^IC80) of 1.0 to 12.1ng/mL.Recoveries from spiked shrimp, eel and crucian at levels of 5.0, 10 and 20μg/kg were in the range of 70.4%¹04.1%, with relative standard deviation ranging from 5.0% to 14.7%. Results indicated that the established dcELISA was suitable for multi-analytes rapid determination of fluoroquinolones residues in aquatic product.