Preconcentration of copper with dithizone-naphthalene for subsequent determination by atomic absorption spectrometry

A simple and convenient method for the separation and preconcentration of copper from aqueous samples has been developed. The procedure is based on the chemical sorption of copper(II) onto a column packed with immobilized dithizone on microcrystalline naphthalene. The trapped copper is eluted with 10 mL of 4 M nitric acid and determined by flame atomic absorption spectrometry. A preconcentration factor of 200 was obtained for a volume of 2 L. The relative standard deviation for the determination of 5 and 10 μg/L copper was 2.2 and 1.7%, respectively. The procedure was successfully applied to the determination of copper in water and alloy samples. The accuracy was assessed through the analysis of certified reference materials or recovery experiments.