丙氨酸增敏催化动力学光度法测定痕量铜(Ⅱ)  

Determination of Trace Copper(Ⅱ)by Catalytic Kinetic Spectrophotometry with Alanine as the Sensitizer

作　　者：赵二劳[1] 张晶[1] 范建凤[1] 

机构地区：[1]忻州师范学院化学系,山西忻州034000

出　　处：《分析科学学报》2010年第6期716-718,共3页Journal of Analytical Science

摘　　要：在pH=4.7的HAc-NaAc缓冲溶液中,以丙氨酸为增敏剂,铜(Ⅱ)能催化过氧化氢氧化依文思蓝使其褪色,据此建立了测定痕量铜(Ⅱ)的新催化动力学光度法。研究了该指示反应的最佳条件,并测得其表观活化能和反应速率常数分别为12.29kJ/mol和3.25×10-4s-1。在优化条件下,铜(Ⅱ)在0.008～0.120μg/mL浓度范围内与△A呈良好的线性关系,相关系数r=0.9999,检出限为5.75×10-9g/mL。方法应用于不同水样、茶叶及几种新鲜蔬菜中痕量铜的分析,相对标准偏差(RSD)小于0.61%,回收率在96.0%～105%之间。A new catalytic kinetic spectrophotometry for the determination of trace copper was established.The method was based on the catalytic effect of copper on the oxidizing discoloring reaction of Evans blue with hydrogen peroxide in HAc-NaAc buffer solution at pH=4.7.The apparent activation energy and the rate constant of the reaction were 12.29kJ/mol and 3.25×10^-4 s^-1, respectively.Under the optimized conditions,the absorbance showed good linearity with the concentration of Cu2＋in the range of 0.008～0.120μg/mL.The regression equation wasA=2.6069c-0.0123,the correlation coefficient was 0.9999,and the detection limit of this method was 5.75×10^-9 g/mL.The proposed method has been used to analyze Cu^2＋in several samples,such as water samples, tea and fresh vegetables with RSD less than 0.61%.

关 键 词：铜(Ⅱ) 依文思蓝 催化光度法 丙氨酸 

分 类 号：O657.32[理学—分析化学]