二溴羧基偶氮胂褪色光度法测定痕量铈  

Dibromocarboxyarsenazo Discoloring Spectrophotometric Determination of Trace Cerium

作　　者：李北罡[1] 李欣[1] 

机构地区：[1]内蒙古师范大学化学与环境科学学院,内蒙古呼和浩特010022

出　　处：《内蒙古师范大学学报（自然科学汉文版）》2009年第2期194-197,共4页Journal of Inner Mongolia Normal University(Natural Science Edition)

基　　金：内蒙古自然科学基金资助项目(200711020214)

摘　　要：研究了稀土元素铈对二溴羧基偶氮胂的褪色作用．结果表明，在0．05mol·L^-1H2SO4介质中，Ce（Ⅳ）对二溴羧基偶氮胂具有很强的氧化褪色作用，且有色溶液的褪色程度与Ce（Ⅳ）量在0．25～10．00μg／25mL范围内符合比耳定律，最大吸收波长为530rim，表观摩尔吸光系数为7．2×10^5L·mol^-1·cm^-1，检出限为4．5μg·L^-1据此建立了一种测定痕量Ce（Ⅳ）的新方法，该法可直接用于红豆、土豆等农副产品中痕量铈的测定，加标回收率为92％～102％，样品不需预处理。结果令人满意。The fading action of the rare earth element cerium to dibromocarboxyarsenazo is studiecl in detail. The results show that the dibromocarboxyarsenazo is oxidized to discolor strongly by trace Ce（Ⅳ） in H2SO4 （0. 05mol·L^-1） medium,and the fading rate with the concentration of Ce（Ⅳ） obeyed Beer＇s law in the linear range of 0. 25 ～ 10μg/25 mL. The maximum absorption wavelength al,d apparent molar absorptivity are 530nm and 7.2×10^6 L·mol^-1·cm^-1 ,respectively. The detection limit is 4.5μg· L^-1. Based on that, a new discoloring spectrophotometric method for determination of trace Ce （Ⅳ） is developed,with which no pretreatment is needed for samples. The method has been applied to the direct determination of trace cerium in rice, potatoes and other agricultural products. The experiments show satis- factory results with the recovery rate 92% ～102 %.

关 键 词：二溴羧基偶氮胂 铈 褪色光度法 农副产品 

分 类 号：O657.32[理学—分析化学]