Rapid and sensitive immunoassays for the detection of lomefloxacin and related drug residues in bovine milk samples

Abstract

The misuse and illegal use of fluoroquinolones (FQs) in animal-based food products have drawn considerable attention in several countries. As a result, there has been an increased demand for efficient detection methods of FQs in food products. In this study, we developed an indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) and immunochromatographic strip device based on a monoclonal antibody against lomefloxacin (LFLX), a second generation FQ. Ic-ELISA had an IC50 value of 0.19 ng/mL with a limit of detection of 0.04 ng/mL in 0.01 M phosphate-buffered saline (PBS). The intra- and inter-assay recovery rates of LFLX in bovine milk samples were 98.02–107.40% and 100.65–107.82%. The immunochromatographic assay of LFLX in PBS and spiked bovine milk samples had visual cutoff values at 1 and 5.0 ng/mL, respectively, with significant cross-reactivity with norfloxacin and enoxacin. The developed ic-ELISA and strip method may assist in the detection of FQs in foods.