Aptamer Affinity Column for Enrichment and Purification of Aflatoxin B1 from Grains Prior to High Performance Liquid Chromatography Detection

Abstract

Aflatoxin B1 (AFB1), a highly teratogenic and carcinogenic secondary metabolite produced by Aspergillus, is commonly found in grains. The complexity of grain composition not only seriously interfere with the effective extraction and separation of AFB1, but also cause problems such as matrix interference and instrument damage, which pose a great challenge in the accurate analysis of AFB1. In this study, an aptamer affinity column for AFB1 analysis (AFB1-AAC) was successfully prepared for the enrichment and purification of AFB1 from grain samples. AFB1-AAC, utilizing an AFB1-specific aptamer as the recognition element, exhibited high affinity and specificity for AFB1. The AFB1 in 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. In order to verify the accuracy of the method, standard materials of AFB1 contaminated corn and wheat were analyzed and the result obtained was in good agreement with the certified values. This study provides a novel and robust method that can be applied to the quantitative determination of AFB1 in grain samples.

Keywords: Aflatoxin B1, Aptamer affinity column, Grain, Sample pretreatment