Fast construction of core-shell structured magnetic covalent organic framework as sorbent for solid-phase extraction of zearalenone and its derivatives prior to their determination by UHPLC-MS/MS.

Magnetic covalent organic framework nanocomposite denoted as Fe3O4@TAPB-Tp with core-shell structure was fabricated via a simple template-mediated precipitation polymerization method at mild conditions. The polyimine network shell was created through the polymerization of 1,3,5-tris(4-aminophenyl)-benzene (TAPB) and 1,3,5-triformyl-phloroglucinol (Tp) in tetrahydrofuran (THF) by the Schiff-base reaction. Featuring with large specific surface area (163.19 m2 g-1), good solution dispersibility, and high stability, the obtained Fe3O4@TAPB-Tp exhibited high adsorption capacities and fast adsorption for zearalenone and its derivatives (ZEAs). The adsorption isotherms showed multilayer adsorption dominated at low concentration and monolayer adsorption at high concentration between the interface of ZEAs and Fe3O4@TAPB-Tp. With the Fe3O4@TAPB-Tp as sorbent, a magnetic solid-phase extraction-ultrahigh performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was established for simultaneous adsorption and detection of five ZEAs in complex samples. The proposed method displayed favorable linearity, low limits of detection (0.003 ~ 0.018 μg kg-1), and good repeatability (2.37~10.4%). The developed method has been applied for real sample analysis, with recoveries of 81.27~90.26%. These results showed that Fe3O4@TAPB-Tp has a good application potential for the adsorption of ZEAs in food samples. Magnetic covalent organic framework nanocomposite (Fe3O4@TAPB-Tp) were quickly fabricated at mild conditions and used as effective adsorbent for magnetic solid-phase extraction of zearalenone and its derivatives (ZEAs) from food samples prior to ultrahigh performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) analysis.