Determination of copper after cloud point extraction by flame atomic absorption spectrometry

A method for the determination of trace copper by flame atomic absorption spectrometry after cloud point extraction was proposed.The analyte was complexd with 2-sulfo-4-methoxy-benzenediazoaminoazobenzene(MOSDAA) and Trition X-114 was added as a nonionic surfactant.The complex formed was extracted into the phase of surfactant,then copper in the complex was determined by flame atomic absorption spectrometry.The effects of experimental conditions such as pH,chelating agent and surfactant,equilibration temperature on cloud point extraction were studied.Under the optimum conditions,the detection limit was 1.1 ng/mL(3σ)for copper,and relative standard deviation was 1.91 %(n=6).The proposed method has been applied to the determination of trace copper in millet and water with satisfactory results.