Fast extraction of aflatoxins, ochratoxins and enniatins from maize with magnetic covalent organic framework prior to HPLC-MS/MS detection

A simple, rapid and sensitive vortex-assisted magnetic solid phase extraction (MSPE) method using core-shell structured magnetic covalent organic frameworks (Fe3O4/COF-TpBD) as adsorbents was established for simultaneous determination of aflatoxins, ochratoxins and enniatins in maize before high-performance chromatography tandem spectrometry detection. Fe3O4/COF-TpBD was facilely fabricated, characterized, and applied for simultaneous extraction of ten mycotoxins from maize. Key parameters affecting MSPE efficiency were investigated. The method possessed good linearity (0.05-50 μg/kg), high sensitivity (0.02-1.67 µg/kg for limits of detection), and satisfactory recoveries (73.8-105.3 %), with relative standard deviations less than 8.5 %. The amount of adsorbent used (5 mg) and the time required (0.5 min each for adsorption and for desorption) for MSPE were greatly shortened in comparison with the previous reports. Therefore, the fabricated Fe3O4/COF-TpBD exhibited a great potential for rapid extraction of common mycotoxins in maize, which can be attributed to its multiple interactions with the target mycotoxins.