Supported hydrophobic ionic liquid on magnetic nanoparticles as a new sorbent for separation and preconcentration of lead and cadmium in milk and water samples

We have prepared a highly selective and efficient sorbent for the simultaneous separation and preconcentration of lead and cadmium ions from milk and water samples. An ionic liquid was deposited on the surface of magnetic nanoparticles (IL-MNPs) and used for solid phase extraction of these ions. The IL-MNPs carrying the target metals were then separated from the sample solution by applying an external magnetic field. Lead and cadmium were almost quantitatively retained by the IL-MNPs, and then eluted with nitric acid. The effect of different variables on solid phase extraction was investigated. The calibration curve is linear in the range from 0.3 to 20 ng mL−1 of Cd(II), and from 5 to 330 ng mL−1 of Pb(II) in the initial solution. Under optimum conditions, the detection limits are 1.61 and 0.122 μg L-1 for Pb(II) and Cd(II) respectively. Relative standard deviations (n = 10) were 2.87 % and 1.45 % for 0.05 μg mL-1 and 0.2 μg mL-1 of Cd (II) and Pb (II) respectively. The preconcentration factor is 200 for both of ions.