三元配合物高灵敏显色反应的研究与应用——钴（Ⅲ）—亚硝基R盐—甲基紫体系

Spectrophotometric Studies and Applications on the Highly Sensitive Colour Reactions of Ternary Complexes--Cobalt(Ⅲ)-Nitroso R Salt-Methyl Violet Syetem

本文研究了在稀盐酸介质中，钴（Ⅲ）与亚硝基Ｒ盐所形成的配合阴离子可以与有机碱阳离子（甲基紫）缔合形成中性缔合分子。在聚乙烯醇存在下，配合物可稳定存在于溶液中。经直线法和平衡移动法测定，配合物中各组分的组成比为Ｃｏ∶Ｒ∶ＭＶ＝１∶３∶６。摩尔吸光系数ε５００＝１．５２×１０５Ｌ·ｍｏｌ－１·ｃｍ－１，采用双峰双波长法则摩尔吸光系数ε５００－６１０＝３．７４×１０５Ｌ·ｍｏｌ－１·ｃｍ－１。钴浓度在０～３．０μｇ／２５ｍｌ范围内符合比尔定律。方法用于茶叶、维生素Ｂ１２、分子筛中钴的测定。

In a medium of diluted HCl,this paper reports the cations of organic basic dye (Methyl Violet)can react to form an ionassociate complex with the anions,formed by cobalt(Ⅲ)ions with nitroso R salt.The product solubilized by polyvinyl alcohol is very stable in the aqueous solution.The composition of each component in the complex is estimated as Co∶R∶MV=1∶3∶6.Its molar absorptivity is found to be 1.52×10 5L·mol -1 ·cm -1 at 500nm.Due to the strong absorption of reagents at 610nm,if the dual-wavelength method is chosen for determination,the molar absorptivity is found to be 3.74×10 5L·mol -1 ·cm -1 .Beers law is obeyed for cobalt in the range of 0￣3.0μg/25ml.The method has been used to determine cobalt in tea leaf,Vitamin B 12 and molecular sieve samples with satisfactory results. \ \