Recyclable magnetic ionic liquid-based aqueous two-phase for rapid extraction of trace quinolones in honey

A novel aqueous two-phase system based on diimidazolium magnetic ionic liquids (MIL-ATPS) was developed for the extraction and determination of trace quinolones (QNs) in honey. The MIL-ATPS achieved extraction efficiencies over 95% and partition coefficients exceeding 200 under optimal conditions, while maintaining good recyclability over at least five cycles without efficiency loss. The method showed satisfactory sensitivity, with limits of detection (LODs) and quantification (LOQs) of 2.853-3.772 μg/L and 8.647-11.43 μg/L, respectively. Satisfactory analytical results were obtained in honey samples, with spiked recovery rates of 97-104% and a relative standard deviation (RSD) below 3%. The intra-day and inter-day precisions ranged from 0.40% to 2.83% and 0.09% to 3.16%, respectively. Density functional theory (DFT) calculations revealed that the MIL could form stable host-guest complexes with the three QNs, providing molecular-level support for the favorable extraction behavior. Our finding provides a rapid, solvent-free, magnetic approach for sensitive antibiotic detection in food.