A magnetically assisted upconversion fluorescence platform integrating magnetic separation and enzymatic amplification for rapid screening of aflatoxin B1 in grain samples

Aflatoxin B1 (AFB1) is a highly toxic mycotoxin that poses a threat to the safety of grains. Therefore, a platform integrating magnetic separation, enzymatic amplification, and upconversion fluorescence detection has been developed for the rapid screening of AFB1. This platform combines PEI-modified magnetic gold nanoparticles, HRP-mediated TMB oxidation reaction, and fluorescence signal transmission based on upconversion nanoparticles (UCNPs), achieving detection through the internal filter effect. The platform exhibits concentration-dependent response within the range of 10–10 6 ng mL −1 , with a detection limit of 5 ng mL −1 . The detection process can be completed within 15 min and has good selectivity. For rice and corn samples with added standards, the recovery rate can reach 80.2% to 99.4%, with a coefficient of variation of 3.14% to 4.75%. This platform provides an effective method for the rapid and selective detection of AFB1 in grain samples.