Facile synthesis of boric acid-functionalized magnetic covalent organic frameworks and application to magnetic solid-phase extraction of trace endocrine disrupting compounds from meat samples.

A facile approach was proposed for the preparation of boric acid-functionalized core-shell structured magnetic covalent organic framework (COF) nanocomposites through employing the FeO nanoparticles as magnetic core, boric acid-functionalized COFs as the shell via sequential post-synthetic modification (denoted as FeO@COF@BA). The synthesized nanocomposites showed large specific surface area, high magnetic responsiveness, and desirable chemical and thermal stability. Combined with HPLC-MS/MS, the as-prepared FeO@COF@BA composite was applied as a sorbent for magnetic solid-phase extraction (MSPE) of endocrine disrupting compounds (EDCs) from meat samples. Under optimal conditions, the method displays low limits of detection (LODs, 0.08-0.72 μg kg) and good precision with relative standard deviations (RSD) lower than 5.4 %. The approach was successfully employed for the extraction and detection of EDCs in blank and spiked beef, chicken and pork samples with recovery ranging from 88.8 to 104.2 %.