MIL-101(Cr)@Fe3O4 nanocomposites as magnetic solid-phase extraction adsorbent for the determination of multiple mycotoxins in agricultural products by ultra-high-performance liquid chromatography tandem mass spectrometry

An efficient and fast magnetic solid phase extraction (MSPE) method was developed using MIL-101(Cr)@Fe 3 O 4 nanocomposites as adsorbent for purification and enrichment of 9 mycotoxins in agricultural products. The successful synthesis of MIL-101(Cr)@Fe 3 O 4 was confirmed via various characterization methods. Several key parameters affecting the performance of the MSPE procedure were extensively investigated including loading solution, elution solution and dosage of adsorbents. Under the optimal sample pretreatment conditions, the complex matrix effects from different agricultural products could be efficiently eliminated and the calibration curves constructed in neat solvent were directly used for the accurate quantification of these mycotoxins. Coupled with the analysis by ultra-high-performance liquid chromatography-tandem mass spectrometry, good linearity (R 2  ≥ 0.991), high sensitivity (limit of quantification in the range of 0.08–0.20 μg kg −1 ), satisfactory recovery (83.5–108.5%) and acceptable precision (RSD, 1.6–10.4%) were obtained. The applicability of the validated method was further verified in real maize, wheat, watermelon and melon samples.