4,6-二溴偶氮胂双波长分光光度法测定粮食和水果中微量稀土  

Application Study with 4,6-dibromoarsenazo Dual-wavelength Spectrophotometry on Rave Earths Respectively in Steed and Agricultural Products

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：《食品科学》2007年第5期290-292,共3页Food Science

基　　金：内蒙古自然科学基金(20040802137)

摘　　要：在pH2．0的氯乙酸-氢氧化钠缓冲介质中，显色剂4，6-二溴偶氮胂与稀土元素能发生高灵敏的显色反应，形成2：1稳定的紫红色络合物，试剂和络合物的最大吸收波长分别为516nm和638nm，建立双峰双波长分光光度法测定稀土元素含量的新方法。结果表明：本法比单波长光度法具有更高的灵敏度，表观摩尔吸光系数达1．56×105；稀土元素含量在0～2ug／ml范围内符合比尔定律，受共存离子的影响小，并具有准确、快速、简便的特点。可不经分离富集，直接用于实际样品中痕量稀土的测定，方法的RSD和回收率分别为2．8％～4．8％和92％～101％。Dual-wavelength spectrophotometry on the color reaction of 4,6-dibromoarsenazo with rare earths has been studied and applied to assay steel and agricultural products. The color reaction of 4,6-dibromoarsenazo with rare earths has high sensitivity and forms stable purple red complexes（l：2） in chioroacetic acid-sodium hydroxide buffer medium at pH 2.0. The maximum absorption wavelengthes of reagent and complexes are at 516 nm and 638 nm, respectively, and the apparent molar absorptivity of the complexes for the dual-wavelength spectrophotometry is ε= 1.56 X 105. The dual-wavelength spectrophotometry is more sensitive than single-wavelength spectrophotometry. Beer＇s law is obeyed in the concentration range of 0-2.0 μg/ml for total rare earths. The method shows simplicity, high sensitivity, better selectivity and accuracy and can be used directly to determine trace rare earths in actual samples without separation and concentration. The recovery of the method is in the range of 92% 101%. The result is satisfactory.

关 键 词：稀土元素 双波长分光光度法 4 6-二溴偶氮胂 粮食 水果 

分 类 号：TS207.3[轻工技术与工程—食品科学]