Effective extraction and detection of aflatoxins in cereals using nitrogen-rich benzodiimidazole linkage magnetic covalent organic framework based solid phase extraction and HPLC-MS/MS analysis
Dan Wei, Jianliang Li, Shuangshuang Zheng, Ming Guo, Jingjing Xu, Qiao Deng, Xu Wang
Abstract
Cereals are frequently contaminated by aflatoxins (AFs). The objective of this study was to develop an efficient extraction materials for rapidly extracting and detecting AFs. A novel amino-functionalized benzodiimidazole linkage magnetic covalent organic framework (Fe 3 O 4 @BB-COF) was simply fabricated by one-step cyclization and aromatization. The Fe 3 O 4 @BB-COF, having multiple N-containing active sites, exhibited excellent extraction capability towards AFs due to synergistic interactions, including the π-π interactions, hydrogen bonding interactions, polar interactions, electrostatic interactions and Lewis acid-base interactions. The Fe 3 O 4 @BB-COF based MSPE method for detecting aflatoxins has advantages of simple operation, short extraction time (6 min), and low material consumption (2 mg). This method exhibited satisfactory linearity (0.05–20 μg/kg), and sensitivity (0.01–0.45 μg/L for the detection limits) and accuracy (76.8–97.1 % for recovery) and was successfully applied for extracting and detecting AFs in cereals. • Nitrogen-rich Fe 3 O 4 @BB-COF was synthesized by simple one-step strategy. • Fe 3 O 4 @BB-COF incorporates iminazole-N, pyridine-N, and amino-N functionalization. • Experimental and DFT studies indicated multi‑nitrogen groups facilitate AFs adsorption. • Fe 3 O 4 @BB-COF was used as adsorbent for effective extraction of AFs. • This method was successfully applied for the reliable detection of AFs in cereal samples.