Synthesis of COF (TAPA-DHTA)-sodium alginate-Ca-polyacrylate composite microspheres as adsorbent for dispersive solid phase extraction of fluoroquinolone antibiotics in food and water prior to the quantification by HPLC-MS/MS.

This work developed hydroxyl‑functionalized covalent organic framework (COF) via ambient-temperature synthesis and integrated it with sodium alginate-Ca²⁺-polyacrylate hydrogel to form composite microspheres (CACMPs) for dispersive solid-phase extraction (dSPE) of five fluoroquinolone antibiotics in milk , eggs and river water. Combining COF with hydrogel can effectively improve the hydrophilicity of adsorbent. The CACMPs do not require centrifugation and can be completely separated within one minute. After five cycles, they still maintain high extraction efficiency (>90 %). Coupled with HPLC-MS/MS, the method achieved a wide linear range (0.01-100 ng/mL), low detection limits (0.05-0.42 μg/kg), and high precision (RSD ≤20.5 %). Validation via spiked samples yielded recoveries of 80.3-117.3 %, confirming reliability for monitoring FQ residues in dairy. Design of CACMPs combines COF adsorption capacity with hydrogel practicality, offering a sustainable, efficient solution for antibiotic analysis in complex matrices.