研究了硫酸铵-1-(2-吡啶偶氮)-2-萘酚-吐温80体系萃取Cu(Ⅱ)的行为及最佳分相条件.结果表明,在pH 6.8-8.5的NaOH-KH2PO4缓冲溶液中,在硫酸铵存在下,Cu(Ⅱ)-1-(2-吡啶偶氮)-2-萘酚的配合物可被吐温80固相完全富集而与Fe3+、Al3+、Co2+、Ni2+、Zn2+等定量分离.配合物最大吸收波长为560 nm,表观摩尔吸光系数7.35×104L·mol-1·cm-1,铜含量在0-14 μg /10 mL范围内服从比耳定律.方法已用于粮食、茶叶等生物样品中痕量铜的测定,测定结果的RSD(n=7)小于4.1%,回收率在98.6%-103.9%之间.

The solid-liquid extraction system of 1-(2-pyridylazo)-2-naphthol (PAN) and Tween-80 for Cu(Ⅱ) using (NH4)2SO4 as salting-out agent was studied and the extraction condition was optimized.In a phosphate buffer medium of pH 6.8-8.5,and by the addition of solid (NH4)2SO4,the coordination complex of Cu(Ⅱ)-PAN was quantitatively extracted into Tween-80 which was separated as solid phase.The co-existing ions,Fe(Ⅲ)、 Al3+、 Co2+、 Ni2+ and Zn2+,were quantitatively separated in this extraction.The apparent molar absorptivity was found to be 7.35×104L·mol-1·cm-1 at the absorption maxima (560 nm) of the coordination complex.Beer′s law was kept in the range of 0-14 μg of Cu(Ⅱ) per 10 mL of solution.In its application to the determination of micro amounts of copper in samples of rice and tea,values of RSD (n=7) obtained were less than 4.1%,and recoveries found were in the range of 98.6% to 103.9%.