铈-二溴羧基偶氮胂褪色光度法的研究及应用  

Study on discoloring spectrophotometry of cerium-dibromocarboxyarsenazo and its application

作　　者：李北罡[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：《冶金分析》2007年第12期73-75,共3页Metallurgical Analysis

基　　金：内蒙古自然科学基金项目(20040802137)

摘　　要：在H2SO4介质中,Ce(Ⅳ)对二溴羧基偶氮胂具有很强的氧化褪色作用,且褪色程度与Ce(Ⅳ)量线性相关,据此建立了一种测定痕量Ce(Ⅳ)的新方法。结果表明,在0.05mol/LH2SO4溶液中,褪色溶液的最大吸收波长为530nm,表观摩尔吸光系数为7.2×106L.mol-1.cm-1。25mL溶液中,有色溶液的吸光度差值与Ce(Ⅳ)量在0.25～10μg范围内呈线性关系,方法检出限为4.5μg/L。该法不需预处理,可直接用于球墨铸铁及合金中痕量铈的测定,测定值与认定值相符合,RSD为1.0%～3.6%。The discoloration reation of dibromocarboxyarsenazo oxidized strongly by trace Ce（Ⅳ） in H2 SO4 medium occurs, and the fading rate is linear with the concentration of Ce（Ⅳ）. In view of the above,a new discoloring spectrophotometry for the determination of trace Ce（IV） was developed. The results show that the maximum absorption wavelength and apparent molar absorptivity are 530 nm and 7.2×10^-6L·mol^-1·cm^-1 ,respectively. The linear range is 0.25 - 10μg for Ce（Ⅳ） in 25 mL of solution , and the detection limit is 4.5μg/L. The method has been directly applied to the determination of trace cerium in spheroidal graphite cast iron and alloys with RSD of 1.0 %--3.6 %,and the results are agreement with the certified values.

关 键 词：铈 二溴羧基偶氮胂 褪色光度法 

分 类 号：O657.3[理学—分析化学]