新试剂5-(4-氯苯基偶氮)-8-苯磺酰氨基喹啉光度法测定微量铜

Spectrophotometric Determination of Copper with 5-(4-chlorophenylazo)-8-(benzenesulfonamido)quinoline

在 p H 8.5的 Na2 B4 O7- HCl介质及有氯化十六烷基吡啶 ( CPC)存在时 ,室温下铜 ( )与 5 - ( 4 -氯苯基偶氮 ) - 8-苯基磺酰氨基喹啉 ( CPBSQ)迅速反应 ,生成络合比为 1∶ 3的有色络合物。研究了反应的最佳条件 ,建立了一个测定 Cu( )的光度分析新方法。Cu( )的浓度在 0～ 1 4.0 μg/2 5 m L 范围内符合比耳定律 ,其摩尔吸光系数为 8.1 2× 1 0 4 L· mol- 1· cm- 1。方法用于面粉、茶叶及奶粉中铜的测定 ,其相对标准偏差为 0 .5 8%～ 1 .2 % ,标准加入回收率为 95 .5 %～ 1 0 4 .5 %。

At room temperature and pH 8.5 Na 2B 4O 7 HCl buffer solution, Cu(Ⅱ) could react rapidly with a 8 sulfonamidoquinoline derivatives: 5 (4 chlorophenylazo) 8 (benzenesulfonamido)quinoline (CPBSQ) to form a 1∶3 complex, which has a maximum absorption at 590 nm. The optimum condition for color reaction has been studied, and a new spectrophotometric method for the determination of Cu(Ⅱ) has been developed. Under the optimum conditions, Beer's law is obeyed in the Cu(Ⅱ) concentration range of 0~14.0 μg/25 mL with a molar absorptivities of 8.12×10 4 L·mol -1 ·cm -1 . The results obtained from the studies on the influence of more than 30 interference ions indicated that a lot of the common ions did not interfere with the determination of Cu(Ⅱ). The method has been used for the determination of copper in flour, tea and milk powder samples with RSD of 0.58%~1.2% and recoveries of 96%~105%.