Fluorescence immunoassay for simultaneous detection typical β-agonists in animal derived food using blue-green upconversion nanoparticles as labels

Common typical beta-agonists mainly include ractopamine (RAC), salbutamol (SAL), and clenbuterol (CLB). In view of the harm to human health causes by the ingestion of animal derived food containing beta-agonists, and a series of regulations have been issued to restrict the usage of beta-agonists as growth promoters. In this work, a fluorescence immunoassay is developed for the simultaneous detection of typical beta-agonists based on blue-green upconversion nanoparticles (UCNPs) combine with magnetic separation. Here, blue-green UCNPs act as a signal amplification source, and magnetic polystyrene microspheres (MPMs) act as an ideal separation medium. Based on a competitive form, capture probe competes (RAC-OVA@MPMs and SAL-OVA@MPMs) with targets to bind corresponding signal probe (anti-RAC antibody@NaYF4:Yb, Tm UCNPs and anti-SAL antibody@NaYF4:Yb, Er UCNPs). The fluorescence difference values of the competitive immune-complex obtained via magnetic separation at 483 nm and 550 nm are proportional to concentrations of RAC and SAL, respectively. The immunoassay has the wide detection linear range from 0.001 to 100 mu g L-1, and the low limit of detection (LOD) is 5.04 x 10(-4) mu g L-1 for RAC, 1.97 x 10(-4) mu g L-1 for SAL, respectively. Meanwhile, use of antibody with same recognition ability for SAL and CLB makes that the fluorescence immunoassay can achieve simultaneous detection of three typical beta-agonists (RAC, SAL, and CLB). This fluorescence immunoassay has good application value and practicability for simultaneous detection of typical beta-agonists in animal derived food.

Automated summary

In this study, a fluorescence immunoassay based on blue-green upconversion nanoparticles and magnetic separation was developed for the simultaneous detection of three typical beta-agonists. The immunoassay showed a wide detection linear range and low detection limits, making it highly valuable for the simultaneous detection of beta-agonists in animal derived food.