Preconcentration of Copper, Cadmium and Lead on Amberlite XAD-4 Resin Functionalized with 2-Hydroxynaphthalene-1-Carbanaldehydethiosemicarbazone and their Determination in Green Tea Leaves by GF-AAS

2-hydroxynaphthalene-1-carbanaldehydethiosemicarbazone loaded XAD-4 chelating resin was synthesized and characterized by FT-IR technique. The use of synthesized resin for preconcentrating Cu2+, Cd2+ and Pb2+ ions was studied using graphite furnace atomic absorption spectrometry (GF-AAS) for metal monitoring in the environmental samples. Various parameters, such as pH, eluent type and concentration, flow rate of sample solution and matrix interference effect on the retention of the metal ions have been studied. The optimum pH for the sorption of the above mentioned metal ions was about 8. Optimum flow rate for quantitative sorption of the metal ions on functionalized resin was found to be 10 mL min-1 whereas 2 M HNO3 was selected as the eluent for quantitative release of the three metal ions from the resin column. Under optimum conditions, recovery of all metal ions was found to be quantitative. The validation of the procedure was carried out by analysis of certified reference materials. The newly developed method was applied to the separation, preconcentration and determination of Cu2+, Cd2+ and Pb2+ in tea leaves collected from the tea gardens of Moulovibazar district of Bangladesh.