Deep eutectic solvent-Ferrofluid based single-step magnetic-assisted liquid-liquid microextraction for Pyrethroid residues determination in vegetable oils by GC–MS/MS

A deep eutectic solvents-based ferrofluids (DES-FFs) material was prepared by combining small-sized Fe 3 O 4 magnetic cores with a ternary choline chloride/sesamol/coumarin (1:3:1) DESs. The material was used for single-step magnetic-assisted liquid-liquid microextraction (MALLME) and determination of 15 pyrethroids (PYs) in vegetable oils by GC–MS/MS. The small-sized Fe 3 O 4 material improved colloidal stability of DES-FFs and enabled rapid phase separation (<10 s). The DES-FFs might leverage enhanced π-π stacking interactions between sesamol/coumarin and PYs, and optimal hydrophilicity-polarity matching, which collectively contributed to the high extraction efficiency for PYs. Comprehensive characterization (HRTEM, XRD, FTIR, TGA, etc.) validated the material's structural integrity, thermal stability and magnetic property. The developed method demonstrated high sensitivity (LODs: 0.91–3.03 ng/mL; LOQs: 3.02–10.09 ng/mL), significantly reduced matrix effect, and good precision (RSD ≤6.92%) for 15 PYs in vegetable oils, with recoveries ranging from 79.88% to 107.90%. Determination of 15 PYs was successfully achieved in both refined and crude vegetable oils.