Triblock copolymer–grafted restricted access materials with zwitterionic polymer outer layers for highly efficient extraction of fluoroquinolones and exclusion of proteins

High-selectivity and high-exclusion restricted access materials (RAMs) benefit the analysis of biological samples. Herein, triblock copolymer–functionalized poly(4-vinylbenzyl chloride- co -divinylbenzene) (P VBC/DVB ) microspheres were prepared via the sequential surface-initiated atom radical polymerization of hydrophobic styrene (St), ionic vinylimidazole (VIm), and zwitterionic sulfobetaine methacrylate (SBMA), affording RAMs with multiple interaction–adsorption sites and zwitterionic polymer exclusion sites on the internal and external surfaces of P VBC/DVB . The preferential extraction of fluoroquinolones (FQs) is realized based on the hydrophobic/π–π/ion exchange interactions due to the grafted poly-St–VIm, and the zwitterionic poly-SBMA block in the triblock copolymers can efficiently exclude various proteins. A sensitive detection method for FQs in chicken was established by solid phase extraction with RAMs as adsorbent combined with UPLC-MS/MS, achieving wide linearity (2.0–200.0 ng mL −1 ), low limit of detection (0.5 μg kg −1 ) and limit of quantification (1.5 μg kg −1 ), and good inter- and intraday precision with satisfactory recoveries (104.1%–117.7% and 115.3%–121.2% with RSDs < 12%).