Environmentally friendly vortex-assisted liquid-phase microextraction using a deep eutectic solvent for lead...

This work presents a simple, environmentally friendly vortex-assisted liquid-phase microextraction (VA-LPME) method using a hydrophobic deep eutectic solvent composed of caprylic acid and menthol (molar ratio 1 : 0.1) for the preconcentration and determination of Pb in seafood samples by flame atomic absorption spectrometry (F AAS). The main parameters affecting extraction performance were optimized, including DES type and volume, solution pH, and the use of diluents. The optimized conditions were: sample volume: 10.0 mL; extractant volume: 100 µL; pH: 7.5; rich-phase diluent: HNO₃-methanol (1 : 0.1); extraction time: 30 s. Under these conditions, the method provided an enrichment factor of 53, a detection limit of 0.9 µg L^-1, and a quantification limit of 2.7 µg L^-1, without the need for complexing agents. Method accuracy was assessed using certified reference material, namely plankton (BCR 414), and by comparison with ET AAS. The method was successfully applied to seafood samples, including oyster, mullet, shrimp, crab, and shellfish, with Pb concentrations ranging from 0.60 to 4.11 mg kg^-1. Overall, the proposed procedure offers an environmentally friendly, efficient, and practical alternative for Pb determination in seafood samples, supporting environmental and food safety analyses.