An aptamer affinity column for purification and enrichment of aflatoxin B and aflatoxin B in agro-products.

We have developed an aptamer affinity column (AAC) for the purification and enrichment of trace aflatoxin B (AFB) and aflatoxin B (AFB) in genuine agro-products through the covalent conjugation of amino modified aptamer and NHS-activated Sepharose. The coupling and working conditions found to be suitable for this AFB-AAC were examined in regard to coupling time (2 min), loading volume (30 mL), and the methanol concentration (< 10%) used in the loading step. The performance of AFB-AAC was then further evaluated in terms of capacity (329.1 ± 13.7 ng for AFB and 162.5 ± 8.9 ng for AFB), selectivity (excellent), reusability (twenty-three times for AFB and twelve times for AFB), and repeatability (92.7% ± 2.9% for AFB and 71.5% ± 3.4% for AFB). Furthermore, the AAC clean-up combined with HPLC-FLD demonstrated excellent linearity over a wide range, good sensitivity with an LOD of 50 pg mL for AFB and 15 pg mL for AFB, and acceptable recovery with different spiking levels in different matrices. Finally, the AAC was successfully applied to analyte AFB and AFB in four types of agro-products as well as a maize flour reference material, and the results were found to be in accordance with those of commercial IACs. This study provides a reference for the analysis of other trace analytes by merely changing the corresponding aptamer and represents a strong contender for immune affinity columns. Graphical abstract An aptamer affinity column for purification and enrichment of aflatoxin B and aflatoxin B in agro-products with the aid of HPLC-FLD and a post-column photochemical derivatization reactor.