Covalent organic frameworks (COFs) have attracted impressive
interest
in separation on aqueous media. Herein, we integrated the stable vinylene-linked
COFs with magnetic nanosphere via the monomer-mediated in situ growth
strategy to construct a crystalline Fe3O4@v-COF
composite for enrichment and determination of benzimidazole fungicides
(BZDs) from complex sample matrices. The Fe3O4@v-COF has a crystalline assembly, high surface area, porous character
together with a well-defined core–shell structure, and serves
as progressive pretreatment materials for magnetic solid phase extraction
(MSPE) of BZDs. Adsorption mechanism studies revealed that the extended
conjugated system and numerous polar cyan groups on v-COF provides
abundant π–π and multiple hydrogen bonding sites,
which are conducive to interact with BZDs collaboratively. Fe3O4@v-COF also displayed enrichment effects to various
polar pollutions with conjugated structures and hydrogen-bonding sites.
Fe3O4@v-COF-based MSPE-high-performance liquid
chromatography exhibited the low limit of detection, wide linearity,
and good precision. Moreover, Fe3O4@v-COF showed
better stability, enhanced extraction performance, and more sustainable
reusability in comparison with its imine-linked counterpart. This
work proposes a feasible strategy on constructing the crystalline
stable magnetic vinylene-linked COF composite for the determination
of trace contaminants in complex food matrices.