Optimization of vortex-assisted supramolecular solvent-based liquid liquid microextraction for the determination of mercury in real water and food samples

Abstract

A novel method was developed for sample preparation for spectrophotometric determination of Hg(II) in water and food samples. The method was based on vortex-assisted supramolecular solvent-assisted liquid-liquid microextraction (VA-SUPRASs-LLME). Analytical parameters such as pH, chelating agent, solvent type and volume, vortex time and salting out effect were optimized. Surface and normal probability plots were drawn for the variables using the optimization data. Microwave-assisted digestion of samples was performed before the extraction procedure. L-cysteine was found to be more effective as a ligand for Hg(II). Five different SUPRASs were prepared and used for the extraction of Hg(II). A 1-decylamine/thymol/water at a 1:2:1 molar ratio assisted by a salting effect was found most effective for optimal extraction. Limits of detection and limit of quantification were found 0.6 μg L−1 and 2.0 μg L−1 with a very good linearity range of 2–350 μg L−1. Intra-day and inter-day precisions were in the range of 1.8–4.0 % with a preconcentration factor 150. The accuracy of the method estimated by analysis of certified reference materials was 96–98.5 %. Finally, the new method was used for the determination of Hg(II) in real water, food samples, and certified reference materials (NIST, IAEQ/W-4(simulated freshwater), and DORM-4; fish protein).