Determination of trace amounts of copper in river and sea water samples by flame atomic absorption spectrometry (FAAS) after cloud-point preconcentration

A new preconcentration method was proposed using the cloud point approach for copper determination. The reagent 1,5-diphenyl-benzoin (Cupron) was used as a complexing agent and Triton X-114 was added as a surfactant. After phase separation, dilution of the surfactant rich phase was carried out using acidified methanol and the copper content was subsequently measured by flame atomic absorption spectrometry. After optimization of the complexation and extraction conditions, the enrichment factor for Cu was found to be 88. The proposed procedure allowed determination of the copper content with the detection limit of 0.04 mu g L-1. The method was successfully applied to copper determination in river and sea water samples. The relative standard deviation for the method was found to be 1.9 % for Cu. The interference effects of some anions and cations were also investigated.