Determination of Aflatoxin B₁ in Grains by Aptamer Affinity Column Enrichment and Purification Coupled with High Performance Liquid Chromatography Detection

Aflatoxin B₁ (AFB₁) is a highly teratogenic and carcinogenic secondary metabolite produced by Aspergillus. It is commonly detected in agricultural products such as cereals, peanuts, corn, and feed. Grains have a complex composition. These complex components severely interfere with the effective extraction and separation of AFB₁, and also cause problems such as matrix interference and instrument damage, thus posing a great challenge in the accurate analysis of AFB₁. In this study, an aptamer affinity column for AFB₁ analysis (AFB₁-AAC) was prepared for the enrichment and purification of AFB₁ from grain samples. AFB₁-AAC with an AFB₁-specific aptamer as the recognition element exhibited high affinity and specificity for AFB₁. Grain samples were enriched and purified by AFB₁-AAC, and subsequently analyzed by high performance liquid chromatography with post-column photochemical derivatization-fluorescence detection (HPLC-PCD-FLD). The average recoveries of AFB₁ ranged from 88.7% to 99.1%, with relative standard deviations (RSDs) of 1.4-5.6% (n = 3) at the spiked levels of 5.0-20.0 μg kg^-1. The limit of detection (LOD) for AFB₁ (0.02 μg kg^-1) was much below the maximum residue limits (MRLs) for AFB₁. This novel method can be applied to the determination of AFB₁ residues in peanut, corn, and rice.