Facile synthesis of magnetic ionic covalent organic frameworks for dispersive magnetic solid-phase extraction of...

In this study, a novel cationic magnetic covalent organic framework (Fe₃O₄@DB-iCOF) was synthesized and applied as an adsorbent in dispersive magnetic solid-phase extraction (DMSPE). The as-prepared material exhibits a high surface positive charge density and uniform pore distribution, offering abundant binding sites for target analytes while maintaining a simple and scalable synthesis procedure. A systematic characterization approach was conducted to evaluate the morphological features, structural properties, and chemical composition of the resulting nanocomposite. The distinct surface charge characteristics of Fe₃O₄@DB-iCOF facilitate efficient and selective extraction of phenolic carboxylic acids (PCAs) through synergistic electrostatic and π-π stacking interactions. When integrated with optimized DMSPE conditions, the developed HPLC-MS/MS method achieved excellent linearity (R² ≥ 0.9986) and low detection limits ranging from 0.003 to 0.05 μg/kg for all target analytes. The method demonstrated satisfactory performance in the analysis of food products derived from broad-leaved plants, yielding recovery rates between 80.96 % and 118.75 %. Notably, this successful application not only presents an innovative strategy for utilizing cationic COFs as magnetic SPE adsorbents but also establishes a robust analytical protocol for the reliable monitoring of PCAs in complex sample matrices.