Fabrication of fluorinated magnetic microporous organic network for selective and efficient extraction of benzoylurea insecticides in tea beverages

In this work, a novel fluorinated magnetic microporous organic network (Fe₃O₄@FMON) was exquisitely designed and synthesized for highly efficient and selective magnetic solid phase extraction (MSPE) of fluorinated benzoylurea insecticides (BUs) from complex tea beverage samples. The Fe₃O₄@FMON exhibited good extraction for BUs via the pre-designed hydrophobic, π-π stacking, hydrogen bonding and specific FF interactions. A sensitive Fe₃O₄@FMON-based MSPE-HPLC-UV method with wide linear range (0.10–1000 μg L⁻¹, R² ≥ 0.996), low limits of detection (0.01–0.02 μg L⁻¹), and large enrichment factors (85.6–98.0) for BUs from tea beverage samples was developed. By decorating F elements within MON's networks, the Fe₃O₄@FMON characterized good hydrophobicity and chemical stability, which could be reused at least 8 times without decrease of recoveries. This work demonstrated the great prospects of Fe₃O₄@FMON for enriching trace BUs from complex substrates and triggered the potential of FMON for sample pretreatment of fluorinated analytes.