Cloud Point Extraction and Flame Atomic Absorption Spectrometric Determination of Cd(II) in Industrial and Environmental Samples

A micelle-mediated separation/preconcentration technique was used for the determination of trace Cd(II) in solid and liquid samples by flame atomic absorption spectrometry. Cadmium ions reacted with ammonium pyrrolidine dithiocarbamate to form a chelate that was extracted from aqueous medium by a non-ionic surfactant Tergitol NP-7 at pH 7. Values of pH, concentrations of ammonium pyrrolidine dithiocarbamate and Tergitol NP-7, temperature, incubation time, sample volume and matrix ions were optimized. The enrichment factor of the method was found to be 25, and the detection and quantitation limits were 1.5 and 3.8 mu g/L, respectively. Assessment of the method was performed with a certified reference material, and the observed concentration of Cd(II) was in good agreement with the certified value. The method was also applied to the determination of Cd(II) in waters and industrial samples. Cd(II) concentrations in two industrial ZnO composite samples were determined between 59 and 69 mu g/g.