阻抑甲基橙褪色催化动力学光度法测定痕量钴(Ⅱ)  

Determination of Trace Cobalt with Inhibiting the Fading of Methyl Orange Catalytic Kinetic Spectrophotometry

作　　者：杨洋[1] 杨森[1] 张琪[1] 王洪福[1] 何黎明[1] 

机构地区：[1]绵阳师范学院化学与化学工程学院,四川绵阳621000

出　　处：《绵阳师范学院学报》2011年第5期58-61,共4页Journal of Mianyang Teachers＇ College

基　　金：绵阳师范学院学生科研项目(hx2010-2011-19)

摘　　要：在稀HNO4介质中，Co（Ⅱ）对高碘酸钾氧化甲基橙褪色反应具有阻抑作用，且阻抑反应的强弱与加入Co（Ⅱ）离子浓度成正比，由此建立了阻抑甲基橙褪色催化动力学光度法测定痕量Co（Ⅱ）的新光度分析方法。研究了最佳实验条件，吸光度为502nm处，阻抑反应吸光度（A）与非阻抑反应吸光度（A。）的差值△A与钴（Ⅱ）质量浓度在0．003—1．0μg／25mL范围内有良好的线性关系，检出限为1．0981×10^-10g／mL。测定了动力学参数，反应为准一级反应，表观活化能为63．24kJ／mol，在80℃下反应的表观速率常数为6．70×10^-4／s。该方法可用于药用VBl2针剂中痕量Co（Ⅱ）测定，回收率在97～102％之间，符合痕量分析要求。With diluted HNO4 as medium, the fading reaction of potassium periodate oxidizing methyl orange can be inhibited by cobalt （Ⅱ） while the force of the inhibitory reaction is proportional to the concentration of cobalt （Ⅱ） added, so a new kinetic analyzing method of trace cobalt （Ⅱ） determination with inhibiting fading of methyl orange catalytic kinetic spectrophotometry was established. The best experimental conditions were discussed. The absorbency difference △A between non - inhibitory reaction （ A0 ） and inhibitory reaction （A） remained good linear relationship with mass concentration of cobalt（Ⅱ） in the range of 0. 003 - 1.0 μg/25 mL. The detection limit was 1. 0981 × 10 ^-10 g/mL, and kinetic parameters were determined which showed that the reaction was pseudo first order. The apparent active energy of the reaction was 63.24 kJ/mol, and the apparent rate constant was 6.70 × 10^-4/s at 80℃. The method can be applied to the determination of VB12 medical injection with the recovery rate between 97 - 102% which met the requirement of trace analysis.

关 键 词：催化动力学光度法 高碘酸钾 甲基橙 钴(Ⅱ) 

分 类 号：Q643.1[生物学—生物物理学]