Time-resolved fluoroimmunoassay for quantitative determination of tylosin and tilmicosin in edible animal tissues

To quantitatively determine tylosin and tilmicosin in edible animal tissues, a time-resolved fluoroimmunoassay (TRFIA) has been developed and validated. For this purpose, desmycosin-O-carboxymethoxylamine-BSA was fixed onto microtiter plates, standards and samples were loaded and, finally, diluted europium-labeled anti-tylosin antibodies were added. Results show that the limit of detection for tylosin was 0.03 ng mL−1 and that for tilmicosin was 0.05 ng mL−1. The recoveries were 73.6% to 120.5%, with coefficients of variation below 15.6% in various biological matrices spiked with tylosin and tilmicosin at concentrations of 50–200 ng g−1. There was good correlation (R 2>0.99) between the TRFIA, an enzyme-linked immunosorbent assay and high performance liquid chromatography data. In conclusion, the new TRFIA is applicable to the detection of tylosin and tilmicosin and is an effective and economical method that will enable high-throughput sample screening. The method is expected to be widely applicable.