dispersive liquid–liquid microextraction based on green type solvents—'deep eutectic solvents'—for highly selective separation and efficient preconcentration of nickel in water samples

This study proposed a fast, feasible, and sensitive method for nickel preconcentration and separation in different actual samples through the use of deep eutectic solvent based dispersive liquid–liquid microextraction (des-dllme). this method involves dissolving a suitable extraction solvent in a dispersive solvent and its rapid syringing into water sample to obtain a turbid solution. phase separation could be then carried out by centrifugation and the analyte can be determined. 2,2′-furildioxime was employed as the chelating agent through formation of a hydrophobic complex with nickel. to reach maximum recovery, some variables including type and volume of dispersive solvent, volume of extraction solvent, ph, 2,2′-furildioxime concentration, and salt concentration were optimized. under optimal conditions, nickel calibration graph was linear in the range of 5.0–100 µg l−1. the detection limit and preconcentration factor were obtained as 1.7 µg l−1 and 40 µg l−1, respectively. finally, this method was successfully applied for the extraction and determination of nickel in water samples with a relative recovery of 98.8–101.0%.