Monoclonal antibody-based solvent tolerable indirect competitive ELISA for monitoring ciprofloxacin residue in poultry samples

This study presents the generation of monoclonal antibodies (mAbs) through cell fusion procedure and the development of mAb-based indirect competitive ELISA (icELISA) for detecting ciprofloxacin (CIP) residue in poultry samples. Under optimal experimental conditions, this assay exhibited a working range of 0.05-83.2 ng/mL, with the half maximal inhibitory concentration (IC50) and the limit of detection values of 0.56 and 0.03 ng/mL, respectively. Cross-reactivity results showed a class-specificity immunoassay and 20-fold dilution in muscle extracts gave an inhibition curve almost the same as that in PBS buffer. It also indicated that the optimised concentrations of pH and NaCl in dilute solution were 7.4 and 0.1 M, respectively, and the icELISA can tolerate higher concentrations of methanol (30%) than acetonitrile (10%) tested. When applied to poultry muscles, the correlation coefficients (R-2) between the icELISA and liquid chromatography-mass spectrometry data were 0.9411 in chicken, 0.953 in duck and 0.894 in geese. Therefore, this assay has the potential to be incorporated into a quantitative monitoring programme for the rapid screening of CIP residue in food.