Simultaneous homogeneous liquid-liquid extraction of Ni(II) and Cu(II) using new vic-Dioxime derivative

A new vic-dioxime derivative (2H-1,4-benzothiazine-2,3(4H)dionedioxime, Oxime I) has been synthesized and investigated as a selective complexing ligand for homogeneous liquid-liquid extraction and preconcentration of Ni2+ and Cu2+ ions. Zonyl FSA has been applied as a phase separation agent. The influence of pH, type, and concentration of water-miscible organic solvent, Zonyl FSA, and Oxime I, as well as the effect of different diverse ions on extraction and determination of Ni2+ and Cu2+ ions has been investigated. Under optimum conditions ([Oxime I]T = 1.2 x 10-3 mol L-1, [THF]T = 16.7 % v/v, [FSA]T = 3.2 % m/v, pH = 4.5), 5 ng of each Ni2+ and Cu2+ in 5.5 ml aqueous phase was extracted quantitatively into 75 μL of the precipitated liquid phase. Limit of detection of the proposed method was 0.004 ng mL-1 for Ni2+ and 0.005 ng mL-1 for Cu2+. The proposed method has been extended over extraction and determination of Ni2+ and Cu2+ ions in different synthetic and natural water samples. (authors)