Synthesis of urea-functionalized magnetic porous organic polymers Fe3O4@PDA@UPOPs for rapid extraction of fluoroquinolones in food samples

It is of great interest in the development of reliable strategies for efficient adsorption and enrichment of drug residues in sample pretreatment. In this paper, urea-based porous organic polymers (UPOPs) were synthesized by the atom economic polymerization reaction of 1,4-phenylene diisocyanate (PPDI) and 1,3,5-tris(4-aminophenyl)benzene (TAPB) under mild conditions. Inspired by the versatility of polydopamine (PDA) coating, the UPOPs were successfully decorated on PDA coated-magnetic nanoparticles (Fe3O4@PDA) via in situ catalyst-free polymerization to afford urea-functionalized porous organic polymers (Fe3O4@PDA@UPOPs). The synthesized adsorbents exhibited good stability, high hydrophicility, microporous and mesoporous structure. The applicability of Fe3O4@PDA@UPOPs was evaluated as effective adsorbents for the magnetic solid-phase extraction (MSPE) of fluoroquinolones (FQs) from food samples (milk, egg and chicken muscle). Combined with high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) analysis, the optimized method featured low adsorbents dosage (2 mg) and rapid extraction (2 min), which provided a wide linear range (0.1–200.0 ng/g, r ≥ 0.9991) and high sensitivity (LODs: 0.04–0.1 ng/g) for FQs determination. Furthermore, controllable magnetism enable the adsorbents could be easily recovered by external magnet and reused at least eight extraction cycles without decreasing the adsorption performance.