表面活性剂存在下钨─5─溴水杨基荧光酮分光光度法的研究与应用

Study and Application of the New Chromogenic Reaction System of Tungsten -5-Bromo-Salicylfluorone in the Presence of Surfactants

研究了显色剂５－溴水杨基荧光酮在表面活性剂Ｔｗｅｅｎ－８０和溴化十六烷基三甲铵存在下与钨（Ⅵ）的显色反应。在强酸性介质中，钨（Ⅵ）与５－溴水杨基荧光酮形成１：２的红色络合物，最大吸收波长为５１８ｎｍ，表现摩尔吸光系数为１．３２×１０５Ｌ·ｍｏｌ－１·ｃｍ－１，钨含量在０～２５μｇ／２５ｍｌ范围内遵守比尔定律。该体系选择性好，灵敏度高，方法简便，已用于水相直接光度法测定合金钢中的微量钨，结果满意。

The colour reaction of tungsten with a colour reagent,5-bromo-salicylfluorone (5-BrSAF),in the presence of Tween-80 and cetyltrimethylammonium bromide (CTMAB), has been studied in this paper. Tungsten reacts with 5-BrSAF in strong acid medium to form a red complex in composition ratio 1:2.The maximum absorbance of the complex is at 518nm with apparent molar absorption coefficient of 1.32×105 L·mol-1.cm-1. Beer's law is obeyed in the range of 0- 25μgW/25ml. The method is sensitive,selective,convenient,rapid, and satisfied with the determination of micro amounts of tungsten in alloying steel without separation.