Selective Cloud Point Extraction and Preconcentration of Copper by the Use of Dithizone as a Complexing Agent

The aim of this work was to develop a selective cloud point extraction method for the separation and preconcentration of copper(II) prior to spectrophotometric determination. For this purpose dithizone was used as a complexing agent and the experimental solution was acidified with sulfuric acid. Triton X-114 was used as a surfactant and after phase separation, based on the cloud point of the mixture, the rich phase was diduted with tetrahydrofuran (THF) and the enriched analyte determined by spectrophotometric analysis. The chemical and thermodynamic variables affecting the complexation and phase separation were optimized. Calibration plot of absorbance vs. concentration was linear within the range of 15-250 ng ml -1 Cu( II ) the limit of detection being 4.6 ng ml -1. The proposed procedure was successfully applied to the determination of copper in liver samples.