Simultaneous Separation and Preconcentration of Trace Amounts of Cu(II), Ni(II), Zn(II), and Cd(II) with Modified Nanoporous Pumpellyite Zeolite

A procedure for determination of trace levels of Cu(II), Zn(II), Ni(II), and Cd(II) by flame atomic absorption spectrometry using a preconcentration system has been proposed. In this system, we used modified nanoporous pumpellyite zeolite loaded with 2-phenyl-4-[1-(2-thienyl) methylidene]-5-oxazolone as a sorbent for extracting Cu(II), Zn(II), Ni(II), and Cd(II) ions from real samples. Several parameters such as pH of the sample solution, amount of nanoporous pumpellyite zeolite, amount of ligand, volumes of sample and eluent, type of eluent, flow rates of sample and eluent, and the effects of diverse ions on the preconcentration were investigated. The LODs for Cu(II), Zn(II), Ni(II), and Cd(II) in the original solution were 2.6, 1.3, 3.2, and 1.1 ng/mL, respectively. The preconcentration factor was 250 for Zn and Ni, 100 for Cd, and 125 for Cu. The developed method was applied to the determination of trace metal ions in certified reference material tea leaves and water samples with satisfactory results.