Abstract:In order to solve the problem of poor stability of signal markers in the rapid detection method of aflatoxin B1 (AFB1), an enzyme-linked immunoassay based on metal organic frameworks (MOFs) was established to detect AFB1 in rice flour. In this study, a biomimetic mineralization method was used to encapsulate horseradish peroxidase (HRP) in the zeolite imidazole framework structure material-8 (ZIF-8) as a signal marker. HRP@ZIF-8 composites could maintain stable catalytic activity under extreme conditions such as alkaline condition and high temperature. On this basis, an indirect competitive immunocolorimetry was established to detect AFB1. The samples containing AFB1 can be directly identified by naked eyes. Under the optimum conditions, the absorbance decreased in the range of 0.01~20 ng/mL with the increase of AFB1 concentration, showing an obvious linear relationship with y =0.03×C[AFB1]+0.78, R2=0.99. The limit of detection was 72 pg/mL, and the precision and specificity were both acceptable. The recoveries of AFB1 in rice flour and flour were 96.00~105.00% and 82.00~110.00%, respectively, with relative standard deviations less than 5%. The method is simple, rapid, sensitive and specific. It can be used for trace determination of AFB1 in cereals such as rice flour and flour.
