Abstract: Based on the principle of indirect competitive reaction combined with magnetic separation using up-conversion nanomaterials, a fluorescence immunoassay for the detection of tyramine in meat products, aquatic products and fermented products was established. The optimal working conditions were obtained as follows: 12 μg of the antibody was coupled with NaYF4Yb, Tm up-conversion nanomaterials to prepare signal probes, 70 μg of the coated antigen was coupled with magnetic polystyrene microspheres to prepare capture probes, the addition amounts of signal probes and sensing probes were 70 μL and 100 μL, respectively, and the competitive reaction time was 30 min. The linear range of the developed method was 0.1–100.0 μg/L, with a detection limit of 0.05 μg/L. The method could specifically recognize tyramine without cross-reaction with its structural analogs or other biological amines. The recoveries of tyramine from spiked samples ranged from 86.44% to 101.62%, with coefficient of variation less than 10%. The proposed fluorescence immunoassay can be applied for rapid detection of tyramine in foods.

Key words: tyramine; polyclonal antibody; immunoassay; upconversion nanoparticles; magnetic separation