双指示剂阻抑动力学光度法测定痕量Ti(Ⅳ)

Determination of Ti(Ⅳ)by Dual-indicator Inhibition Kinetic Spectrophotometry

在硫酸介质中,Fe(Ⅲ)能催化H2O2氧化番红花红T和灿烂甲酚蓝双指示剂混合体系氧化褪色,Ti(Ⅳ)对该氧化褪色反应有灵敏的阻抑作用。测定含有Ti(Ⅳ)的阻抑体系和不含Ti(Ⅳ)的空白体系在波长520nm和630nm处的吸光度,发现在一定条件下,两波长处的吸光度变化之和(△A)与Ti(Ⅳ)的浓度之间存在线性关系,由此建立了双指示剂阻抑动力学光度法测定Ti(Ⅳ)的新方法。研究了反应体系的吸收光谱并优化了反应条件。该方法测定Ti(Ⅳ)的线性范围为4.0～110μg·L-1,检出限为0.12μg·L-1。对40.0μg·L-1Ti(Ⅳ)标准溶液11次平行测定,其相对标准偏差为2.1%。该方法灵敏度高,用于发样中Ti(Ⅳ)含量的测定,结果满意。

A dual-indicator inhibition kinetic spectrophotometric method for the determination of Ti（Ⅳ） has been established,which was based on the inhibition effect on decolorization reaction of Safranine-T and Brilliant cresyl blue with H2O2in the presence of catalyst Fe（Ⅲ）.The absorbance of the system with and without Ti（Ⅳ）at 520nm and 620nm were measured,respectively.The optimum conditions of this reaction were studied in detail.The calibration curve was linear in the range of 4.0～100.0μg·L^-1 Ti（Ⅳ）and the detection limit of method was 0.12μg·L^-1.The relative standard deviation for 40 μg·L^-1 Ti（Ⅳ）was 2.1%（n=11）.This method was simple and sensitive.It was applied to the determination of Ti（Ⅳ）in samples with satisfactory results.