Preparation and modification of Fe3O4@SiO2@KOH&CD-OOR and its application to the detection of polycyclic aromatic hydrocarbons (PAHs) in food samples.

Abstract

A green strategy was developed to modify cyclodextrin-based metal-organic frameworks (CD-MOFs) for fabricating magnetic solid-phase extraction (MSPE) adsorbents targeting polycyclic aromatic hydrocarbons (PAHs). β-cyclodextrin-based MOFs (KOH&β-CD) were synthesized and functionalized with four edible organic compounds (ellagic acid, chlorogenic acid, stearic acid, and tyrosine) to concurrently improve aqueous stability and enhance PAHs recognition. The modified MOFs were then covalently grafted onto Fe3O4@SiO2 magnetic cores and silane-capped, yielding four magnetic composites (Fe3O4@SiO2@MOFs-1-4). Comprehensive characterization confirmed successful fabrication. Adsorption evaluation toward six PAHs (anthracene, fluoranthene, pyrene, benz[a]anthracene, benzo[a]pyrene, and benzo[g,h,i]perylene) revealed high affinity, with the ellagic acid-modified composite exhibiting a maximum capacity of 1.99 mg·g-1 for benzo[g,h,i]perylene. The process followed the Freundlich isotherm and pseudo-second-order kinetic model, indicating multilayer chemisorption. After optimizing MSPE parameters, a method coupling MSPE with HPLC-FLD was established, offering wide linear ranges (1-3500 ng), low detection limits (0.5-5 ng), and satisfactory precision (RSD < 14.1%). When applied to spiked and real food samples (sausage and flour), the method delivered superior recoveries (84.7-116.9%) and better precision compared to the Chinese national standard method (GB 2762-2022), demonstrating its reliability and potential for monitoring trace PAHs in complex food matrices using green food-grade adsorbents.