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Development of an ultrasensitive ic-ELISA and immunochromatographic strip assay for the simultaneous detection of florfenicol and thiamphenicol in eggs

Lei, Xianlu, Xu, Liguang, Song, Shanshan, Liu, Liqiang, Kuang, Hua
Food and agricultural immunology 2018 v.29 no.1 pp. 254-266
antibiotics, cross reaction, eggs, enzyme-linked immunosorbent assay, florfenicol, immunoaffinity chromatography, inhibitory concentration 50, methanol, monoclonal antibodies, nanogold, pH, phenols, screening, sodium chloride
An ultrasensitive monoclonal antibody-based gold nanoparticle immunochromatographic strip assay and indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) were developed to detect florfenicol (FF) and thiamphenicol (TAP) in egg samples. The ic-ELISA, with optimized pH, methanol content and sodium chloride content, exhibited an IC₅₀ value of 0.2 ng/mL for FF and 0.27 ng/mL for TAP, with the working range of 0.05–0.77 and 0.05–1.42 ng/mL, respectively. The optimized ic-ELISA showed negligible cross-reactivity with other phenols and broad-spectrum antibiotics. The recoveries in egg samples using the ic-ELISA ranged from 84% to 115% with a coefficient of variation of less than 5%. Based on this monoclonal antibody, a rapid and ultrasensitive immunochromatographic strip assay was developed with a cutoff value of 1 ng/mL for FF and TAP. Our results indicated that both developed methods were highly useful for screening FF and TAP in eggs.