Simultaneous preconcentration and measurement of ultra-trace Cd(II), Pb(II), and Hg(II) from food samples using deep eutectic solvents in a green approach and employing ICP-OES

The determination of trace amounts of cadmium, mercury, and lead ions in food samples is of great importance due to their hazardous effects on human health. Direct measurement of the analytes is not feasible due to their extremely low concentrations within complex food matrices, and thus, an efficient sample preparation method is required. Therefore, by designing a novel deep eutectic solvent and applying it in the dispersive liquid–liquid microextraction method with high clean-up and compatibility with the analyzer, many of these challenges have been addressed. The accuracy of the synthesized solvent was confirmed by FT-IR and H-NMR analyses. Additionally, the factors affecting analyte extraction were optimized using OVAT and RSM approaches. According to results obtained from ICP-OES analysis, the linear ranges for cadmium (II), mercury (II), and lead (II) were 0.2–20, 0.5–50, and 2.2–200 ng mL⁻¹, respectively. The limits of detection ranged from 0.06 to 0.64 ng mL⁻¹, and the relative standard deviation (RSD%) was below 3.61 (n=5). Therefore, it can be concluded that the synthesized solvent employed in the selected method exhibits high capability for the extraction and preconcentration of the target analytes in various food samples.