Enhanced by ionic liquids: Magnetic molecularly imprinted polymers-magnetic solid-phase extraction-UHPLC-UV for sensitive detection of benzimidazoles in multiple food matrices.

Benzimidazoles (BZDs) as fungicides and veterinary drugs may remain in various food matrices, posing potential risks to human health. It is challenging to detect trace BZDs under complex matrix interferences. In this study, ion liquid magnetic molecularly imprinted polymers (IL-MMIPs) for the selective extraction of six BZDs from complex matrices were synthesized via surface imprinting technology with vinyl-functionalized Fe₃O₄@SiO₂ as magnetic carriers. Importantly, the synthesized 1-vinyl-3-amidomethylimidazolium chloride ([VAFMIM]Cl-IL) was used as the functional monomer, which could form π-π, hydrogen bonds, electrostatic interactions, ion exchange, and hydrophobic interactions with BZDs. A series of adsorption test results demonstrated that IL-MMIPs exhibited superior selectivity, with high imprinting factors (3.77-4.41) and excellent adsorption capacities (18.26 mg/g). Furthermore, coupling with ultra-high performance liquid chromatography (UHPLC) analysis, an effective, sensitive and selective analysis method based on IL-MMIPs-MSPE-UHPLC integrated technology was established and validated for the quantification of 6 BZDs from multiple food matrices. The results showed remarkable sensitivity with limits of quantification 1.5-10.0 μg/kg and expected recoveries (85.1 %-103.6 %). The method satisfied the detection standards of China and the European Union (EU) and had been applied to food matrices including pork, milk, eggs, drinking water, grapes, cucumbers samples. Finally, trace amounts of thiabendazole were detected only in grapes (533 μg/kg) and eggs (79 μg/kg), demonstrating practical significance for detecting trace BZDs in complex matrices.