Magnetic Deep Eutectic Solvent-Based Vortex-Assisted Liquid-Phase Microextraction for Mercury Determination in Seafood Samples

This study aimed to develop and validate a vortex-assisted liquid-phase microextraction (VA-LPME) method based on a magnetic deep eutectic solvent (MDES) for the determination of mercury in seafood samples by cold vapor atomic absorption spectrometry (CV-AAS). The MDES was prepared from menthol and octanoic acid, and Fe 3 O 4 nanoparticles were incorporated to impart magnetic responsiveness, enabling rapid phase separation without centrifugation. Experimental conditions were optimized using a univariate approach, including DES composition (menthol:octanoic acid, 1:3), nanoparticle mass (75 mg Fe 3 O 4 ), agitation mode (vortex), extraction time (50 s), extraction solvent volume (100 µL), and pH (4.2). Under the optimized conditions, the proposed method achieved a detection limit of 0.09 µg L −1 and an enrichment factor of 51. Accuracy was confirmed by the analysis of certified reference materials, with measured values in good agreement with the certified values. The method was successfully applied to the determination of mercury in shellfish, sea bass, oyster, and crab samples, demonstrating its suitability for complex food matrices. The proposed procedure combines good analytical performance with low solvent consumption, simple operation, and a moderate green profile (AGREEprep = 0.54), supporting its potential for routine mercury monitoring in seafood.