微乳液介质中5′-硝基水杨基荧光酮光度法测定铜(Ⅱ)

PHOTOMETRIC DETERMINATION OF COPPER(Ⅱ) WITH 5′-NITROSALICYLPHE- NYLFLUORONE IN CATIONIC-MICROEMULSION MEDIUM

研究了阳离子微乳液CTMAB/n C5H11OH/n C7H16/H2 O介质中Cu(Ⅱ )与 5′ NSF的显色反应。结果表明 ,阳离子微乳液对Cu(Ⅱ )与 5′ NSF显色体系有较好的增敏作用 ,在pH 6.5的KH2 PO4 Na2 HPO4 缓冲体系中 ,Cu(Ⅱ )与 5′ NSF形成 1∶2的紫红色配合物 ,λmax为 5 60nm ,ε560 =1.38× 10 5L·mol- 1·cm- 1,Cu(Ⅱ )在 0～ 6.5 μg/ 2 5ml范围内服从比耳定律。方法用于粮食、茶叶、水和饮料中微量铜的测定 ,回收率在 97.5 %～ 10 3.5 % 。

The chromogenic reaction of Cu(Ⅱ) with 5′ nitrosalicylphenylfluorone (5′ NSPF) in a cationic microemulsion medium composed of CTMAB/ n C 5H 11 OH/ n C 7H 16 /H 2O buffered at pH 6.5 with KH 2PO 4 Na 2HPO 4 was studied. Copper(Ⅱ) reacts with 5′ NSPF to form a 1∶2 complex. The absorption maxima lies at 560nm and the molar absorptivity is found to be 1.38×10 5L·mol -1 ·cm -1 . Beer′s law is obeyed in the range of 0～6.5μg/25ml. This method has been applied to the determination of copper(Ⅱ) in food, tea, water and drink with satisfactory results.