Determination of cadmium(II), copper(II) and zinc(II) in water samples by flame atomic absorption spectrometry after cloud point extraction

Abstract

A preconcentration method for determination of low concentrations of Cd(II), Cu(II), and Zn(II) in water, using cloud point extraction is proposed. The analytes in the initial aqueous

solution have been complexed with 8-hydroxyquinoline, with 0.06% (<i>w/v</i>)<i> </i>Triton X-114 added as surfactant. The complexation allows the separation of the analytes from other elements, which are not complexed. After phase separation, based on the c loud point of the mixture and dilution of the surfactant-rich phase with acidified methanolic solution, the enriched analytes have been determined by flame atomic absorption spectrometry. After

optimization of complexation and extraction conditions, good enrichment factors have been obtained. The detection limits are 0.15 ng ml^-1 for Cd(II), 0.72 ng ml^-1, for Cu(II) and 0.03 ng ml^-1 &nbsp;, for Zn(II) in the initial solution. The relative standard deviations are lower than 3.1 %. The method has been applied for analysis of the studied ions in tap water and river water samples. The method has been validated by the analysis of standard reference material.