4,5-二溴邻硝基苯基荧光酮分光光度法测定微量锰

SPECTROPHOTOMETRIC DETERMINATION OF TRACE AMOUNTS OF MANGANESE WITH DBONPF

研究了在表面活性剂ＣＴＭＡＢ和Ｔｗｅｅｎ－８０存在下，Ｍｎ（Ⅱ）与４，５－二溴邻硝基苯基荧光酮（ＤＢＯＮＰＦ）的显色反应．在ｐＨ８．０～９．６的缓冲介质中，Ｍｎ（Ⅱ）与ＤＢＯＮＰＦ形成１∶２蓝紫色配合物，其最大吸收波长λｍａｘ为６００ｎｍ，表观摩尔吸光系数ε为１．１２×１０５Ｌ·ｍｏｌ－１·ｃｍ－１，Ｍｎ（Ⅱ）含量在０～２００μｇ·Ｌ－１范围内符合比尔定律，是光度法测定锰的高灵敏体系之一．拟定方法用于茶叶样品中微量锰的测定。

The conditions of colour reaction of manganese(Ⅱ) with 4,5-dibromo-o-nitro phenyl fluorone(DBONPF) in the presence of CTMAB and Tween-80 were studied.It was found that manganese(Ⅱ) reacts with DBONPF in a medium of pH8.0～9.6 to form a 1∶2 complex with maximum absorption at 600nm.The molar absorptivity of the complex is 1.12×10 5 L·mol -1 ·cm -1 .Beers law is obeyed for manganese(Ⅱ) in the range of 0～200μg·L -1 .Trace amounts of manganese in tea have been determined by proposed method and the results obtained are satisfactory.