Construction Of Magnetic Hybrid Porous Frameworks For Enrichment And Determination Of Aflatoxin

Recently,food safety has become a prominent issue in public health with the rapid growth of food supply and consumption.Food hazards such as biotoxins,heavy metal ions,pesticides and veterinary drug residues are important factors that would threaten human health.Aflatoxins,a class of secondary metabolites produced by Aspergillus fungi,have high toxicity,immunosuppression and carcinogenicity as a typical representative of biological toxins.Great effort has been made in developing adsorptive materials for effectively probing aflatoxins due to its"small content but high toxicity".Among them,the new adsorbent material shows promising application in realizing high sensitivity,high selectivity and simple AFT enrichment detection.In this paper,a new type of magnetic composite porous framework material was constructed as sample pretreatment materials to establish a high-efficiency enrichment and high-sensitivity detection method for aflatoxins.The core of Fe₃O₄microspheres was coated by metal organic framework crystals（UiO-66-NH₂）,and then a microporous organic network（MON）layer was introduced onto the surface of the magnetic composite through a Sonogashira reaction to obtain magnetic solid phase extraction（MPSE）adsorbent Fe₃O₄@UiO-66-NH₂@MON.The adsorbent exhibited excellent magnetic separation ability,effectively simplified the pretreatment steps,and the MON coating significantly improved the hydrophobicity of the whole adsorbent,which greatly facilitated its application in actual samples.The established method combined with high performance liquid chromatography-fluorescence detector（HPLC-FLD）has a correlation coefficient R²≥0.999 for the four AFT detections,the detection limit in the range of 0.15-0.87μg L^-1,and the RSD in the range of 2.2%-3.0%.It proved that this method is in line with the requirements of the methodology with good selectivity and sensitivity.In order to verify the practicability of the proposed method,it was applied to the detection of AFT in corn,rice and millet,and the recovery rate of standard addition was between87.3%and 101.8%.In summary,the magnetic composite porous framework material prepared in this research and the established MPSE-HPLC-FLD detection method has broad application prospects in the detection of AFT enrichment in complex matrices.