Facile preparation of novel COFs functionalized magnetic core-shell structured nanocomposites and used for rapid detection of trace polycyclic aromatic hydrocarbons in food

A facile and rapid magnetic solid phase extraction (MSPE) based on magnetic covalent organic framework and coupled with high performance liquid chromatography diode array detection (HPLC-DAD) has been developed for detection of 11 kind of polycyclic aromatic hydrocarbons (PAHs) in food samples. In this paper, the novel magnetic core-shell structured (Fe3O4@COFs) nanocomposites were consisted with the magnetic Fe3O4 nanoparticles (NPs) as a core, and 1,3,5-tris (4-aminophenyl) benzene (TAPB) and 2,5-dihydroxyterephthalaldehyde (DP) as two ligands for building shell outside of the core. These new nanocomposites were applied as superior adsorbent to enrich the PAHs due to their merits of large specific surface area, highly porosity and excellent thermal stability. The conditions that may affect the enrichment efficiency in MSPE process, including desorption solvent, amount of sorbent, extraction time, desorption time and desorption adsorption volume were investigated systematically. By combining MSPE with HPLC-DAD, an effective method for the detection of trace PAHs was successfully developed, which exhibited good linearity with R-2 ranging from 0.9954 to 0.9988, satisfactory recoveries in the range of 83.2-119.3%, and the relative standard deviations (RSD) was lower than 5.8%. In addition, the proposed MSPE-HPLC-DAD method was shown excellent ability to enrich trace PAHs effectively in food samples and potential application in extract other aromatic compounds.