Carboxyl-functionalized magnetic amide-linked covalent organic framework for efficient extraction of multi-class mycotoxins from soybeans prior to HPLC-MS/MS analysis

Mycotoxins co-contamination in soybean poses great risks to human health, however, due to their diverse structures, it is difficult to simultaneously extract and detect these multi-mycotoxins. By incorporating modification of hydrophilic carboxyl groups with the hydrophobic properties of covalent organic frameworks, a stable cubic carboxyl-functionalized magnetic amide-linked covalent organic framework were fabricated, characterized and utilized as adsorbents for magnetic solid phase extraction (MSPE) of eleven frequently detected mycotoxins from soybeans followed by HPLC-MS/MS analysis. The key MSPE parameters were screened using the Plackett-Burman design and optimized with the Box-Behnken design for response surface methodologies. Under the optimal experimental conditions, the linear range was 0.2–50 μg/kg, the limits of detection were 0.1–1.4 μg/kg. The established method was applied for the soybean analysis with satisfactory recoveries (70.8–108.3%) and precision (intra- and inter-relative standard deviations of 2.1–9.2% and 1.6–11.1%, respectively). With proper modification, this method may have great application potential for simultaneously analyzing and monitoring the multi-mycotoxin contamination in foods to ensure consumer safety and public health.