Quantum dots-based fluorescence immunoassay for detection of tiamulin in pork

Tiamulin (TML) is a kind of diterpenoid veterinary antibiotic. If abused, it will cause residues in edible tissues of animals and endanger human health. Thus, a facile, sensitive, and accurate method is essential for TML detection. In this study, TML complete antigen was synthesized by oximation and active ester method, and monoclonal antibodies with high specificity and sensitivity were prepared. ZnCdSe/ZnS quantum dots (QDs) coupled with goat anti-mouse IgG were used as a fluorescence detection probe to establish indirect competitive fluorescent immunosorbent assay (icFLISA) for the determination of TML in pork. The 50% inhibitory concentration (IC 50 ) of the icFLISA was 0.069 ng/ml, and the limits of detection (LOD) were 0.309 pg/ml. The recovery of the spiked pork samples for the icFLISA ranged from 85.6 to 96.8%, and the coefficient of variation (CV) was less than 9.4%. The results showed that the icFLISA based on ZnCdSe/ZnS QDs was more sensitive than the traditional indirect competitive enzyme-linked immunosorbent assay for the detection of TML in edible animal tissues.