4—[(5—氯—2—吡啶)偶氮]—1.3—二氨基苯分光光度法测定微量铜(Ⅱ)

Spectrophotometric Determination of Microamount of Copper in Minerals and Alloys with 4-[(5-chloro-2-pyridyl)-azo]-1, 3-diaminobenzene

本文研究了光度法规定微量铜的新方法,试剂5-Cl-PADAB能与铜发生灵敏的显色反应,生成二元络合物Cu(Ⅱ)-5-Cl-PADAB,选择性较高。在pH=4.6～6.2的邻苯二甲酸氢钾的缓冲体系中,试剂与铜形成橙红色络合物,最大吸收波长为535nm,摩尔吸光系数为4.5×10~4,络合比Cu(Ⅱ):5-Cl-PADAB=1:2,在0～18μg/25mL区间内符合比尔定律。在磺基水杨酸的掩蔽下,一般常见的30多种离子不干扰测定,该方法用于合金和矿样中微量铜的测定,结果令人满意。

A new sensitive and selective photometric method has been developedfor the determination of microamount of copper by the formation of Cu(Ⅱ)-5-Cl-PADAB complex. The optimal absorption of the complex is at 535nm.Its molar absorption coefficient is 4.5x10^4 in the range of 0-18μg/25mL.The molar ratio of copper to 5-Cl-PADAB is established as 1:2. Thegiven amounts of common ion show no interference when sulfosalicylicacid exists. This method has been applied to determine Cu(Ⅱ) in mineralsand alloys with satisfactory results.