Rapid and ultrasensitive detection of 3-amino-2-oxazolidinone in catfish muscle with indirect competitive enzyme-linked immunosorbent and immunochromatographic assays

Abstract

In this study, we developed an indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) and an immunochromatographic assay to detect the furazolidone metabolite, 3-amino-2-oxazolidinone (AOZ). The detection of AOZ was based on the AOZ derivative 3-([2-nitrophenyl]methyleneamino]-2-oxazolidinone (2-NPAOZ). 3-([(3-Carboxyphenyl)methylene]-amino)-2-oxazolidinone (2-CPAOZ) was used as the immunizing hapten and a conjugate of AOZ and glyoxylic acid (AOZ-A) was used as the coating hapten. The monoclonal anti-2-NPAOZ antibody, 5G12, was generated with a half-inhibitory concentration (IC50) of 0.2 ng/mL and a line of 0.06–0.66 ng/mL. Its cross reactivity with other analogues was less than 8%. Spiked catfish samples (0.1, 0.2, and 0.5 μg/kg) were analyzed with the proposed system. The ic-ELISA showed a recovery range of 86.2–118.5% and the intra-assay and inter-assay coefficients of variation ranged from 4.3% to 9.4%. Under the optimum assay conditions, the immunochromatographic assay had a visual cut-off value of 0.5 μg/kg in catfish samples. Both methods can be used to detect AOZ in catfish samples.