Cloud point extraction for the determination of trace copper in water samples by flame atomic absorption spectrometry

Cloud point extraction has been used for preconcentration of trace amount of copper. The analyte was complexed with 1,2-dihydroxyanthraquinone-3-sulfonic acid sodium salt, and octylphenoxypolyethoxyethanol was added as a surfactant. The effects of experimental conditions such as pH, concentration of chelating agent and surfactant, equilibration temperature and time on cloud point extraction were studied. Under the optimum conditions, preconcentration of a 12 mL sample solution permitted the detection of 1.07 ng mL^-1 of copper with an enrichment factor of 21. The method was applied to the determination of trace copper in water samples.