Cloud point extraction and flame atomic absorption spectrometry determination of trace amounts of copper(II) ions in water samples.

Cloud point extraction was used with lipophilic Schiff base N,N'-bis(2-hydroxyacetophenone)-1,2-propanediimine (L) as a pre-concentration step prior to flame atomic absorption spectrometry determination of trace amounts of copper in water samples. The process is based upon the formation of Cu(II)/L complexes soluble in a micellar phase composed by the non-ionic surfactant Triton X-114. These complexes are then extracted into the surfactant-rich phase, at above its cloud point temperature. The parameters affecting the extraction efficiency, i.e. pH of aqueous solution, concentration of the Schiff base, amount of the surfactant, incubation temperature, and time were investigated. Under the optimum experimental conditions, the calibration graph was linear in the range 0.1-1300 ng ml(-1) with a limit of detection of 0.06 ng ml(-1). The proposed method was successfully applied for the determination of copper in various water samples.