Determination of trace amount of copper in water samples by cloud point extraction:flame atomic absorption spectrometry

Using 1-(2-pyridylazo)-2-naphthol(PAN)as chelating agent,Triton X-114 as surfactant with HNO_3-ethnol as regulator of viscosity,pH=7,the determination conditions of copper by cloud point extraction—flame atomic absorption spectrometry(CPE-FAAS)method—were optimized.Under the optimal conditions,the detection limit of copper was 0.33μg/L.The enrichment factor was 50-fold for copper.The regression equation was A=0.0449 c+0.0071. The proposed method was successfully applied to the determination of trace quantities of copper in four water samples,including tap water,mineral water,wall water and river water,with the sati- sfactory recoveries ranging from 97% to 104%.