Solid phase extraction on multiwalled carbon nanotubes and flame atomic absorption spectrometry combination for determination of some metal ions in environmental and food samples

In this study, a new sensitive and simple method for simultaneous separation and preconcentration of Cu2+, Zn2+, Pb2+, and Cd2+ ions from various real samples prior to their measurements by flame atomic absorption spectrometry has been developed. The proposed method is based on the utilization of multiwalled carbon nanotube in combination with (E)-N1-(4-nitro-benzylidene)-N2-(2-((E)-4-nitrobenzylideneamino)ethyl) ethane-1,2-diamine as a solid phase extractant. The separation parameters for effective adsorption of Cu2+, Zn2+, Pb2+, and Cd2+ ions, including the effects of pH, amount of ligand, sample and eluent flow rate, and common coexisting ions were examined. The optimum pH for the separation of Cu2+, Zn2+, Pb2+, and Cd2+ ions on the new sorbent was 6.0. The detection limits based on 3 sigma (n = 15) for Cu2+, Zn2+, Pb2+, and Cd2+ ions was 0.69, 0.48, 8.9, and 0.25 ng mL-1 while respective preconcentration factor for Cu2+, Zn2+ ions was 80 and for Pb2+ and Cd2+ ion was 20 and 60, respectively, with relative standard deviations between 0.7% and 5.8%. The proposed preconcentration procedure was applied to the analysis of various real samples.