铬(Ⅲ)-二溴茜素紫-乳化剂OP体系显色反应研究及应用

Study on the Colour Reaction of Cr (Ⅲ) Dibromoalizarin Violet Emulsifier OP System and Its Application

本文研究了在乳化剂ＯＰ存在下，铬（Ⅲ）与２，７－二溴茜素紫（ＤＢＡＶ）的显色反应条件，建立了测定微量铬的分光光度法。在１．８×１０－２ｍｏｌ／ＬＨＣｌ酸度下，９５℃的水浴中保温３５～４５ｍｉｎ钟，铬（Ⅲ）与二溴茜素紫生成灵敏度很高的黄色配合物，其最大吸收峰位于４１２ｎｍ，摩尔吸光系数ε４１２＝１．１８×１０５Ｌ．ｍｏｌ－１．ｃｍ－１，铬（Ⅲ）含量在０～５μｇ／２５ｍｌ范围内服从比耳定律。以氟化钠为掩蔽剂，可用于测定天然水、电镀废液及含铬污水中的微（痕）量铬。

,This paper studies the colour reaction condition of Cr(Ⅲ) with 2,7 dibromoalizarin violetin the present of emulsifier OP, and sets up the spectrophotometry for measuring the trace Cr. Keeping for 35-45 minutes in the water bath at 95 ℃,the high sensitive yellow complex is formed by the reaction of Cr(Ⅲ) with dibromoalizarin violet in 1.8×10 -2 mol/L HCl medium. The molar absorption coefficient ε 412 is 1.18×10 5 L\5mol -1 \5cm -1 at the maximum absorption peak of 412 nm. Beer's Law is obeyed when the content of Cr (Ⅲ) is in the range 0～5 μg /25 ml. Taken NaF as masking agent, it can be used for measuring the trace C r (Ⅲ) in the natural water, electroplate solution and Cr bearing waste water with satisfactory results.