十二烷基磺酸钠存在下偶氮胂Ⅲ光度法测定钢样中稀土总量  

Spectrophotometric determination of total rare earths in steel with arsenazo Ⅲ in the presence of sodium dodecylsulfonate

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2期67-69,共3页Metallurgical Analysis

基　　金：内蒙古自然科学基金项目(20040802137)

摘　　要：研究了溴化十六烷基三甲基铵、十二烷基磺酸钠、吐温-80、乳化剂OP和聚乙烯醇5种表面活性剂对稀土-偶氮胂(Ⅲ)-乙醇显色反应的影响和在十二烷基磺酸钠存在下,偶氮胂Ⅲ分光光度法测定稀土的条件。结果表明:只有十二烷基磺酸钠对显色反应有明显的增敏作用,其余几种效果不明显。在pH28的HCl-NaAc缓冲溶液中和十二烷基磺酸钠存在下,偶氮胂Ⅲ与稀土显色反应有较高的灵敏度,表观摩尔吸光系数ε=9.5×104L.mol-1.cm-1,试剂和络合物的最大吸收波长分别为540nm和655nm,在25mL显色溶液中稀土质量在0～50μg范围内符合比尔定律。所建立的方法直接用于低合金钢标样中稀土含量的测定,结果与认定值十分吻合,RSD在0.37%～1.6%范围内。Influences of five surfactants like hexadecyltrimethylammonium bromide（CTMAB）,sodium dodecylsulfonate（SDS） ,Tween-80,polyvinyl alcohol（PVA）, emulson OP on the color reaction of rare earths, arsenazoⅢ and alcohol were studied. Results showed that only SDS had an effect of enhancing sensitivity. In the HAc-NaAc medium at pH 2.8 and in the presence of SDS,rare earth formed a stable colored complex with arsenazo Ⅲ, the maximum absorption wavelength of the reagent and complex were at 540nm,and 655nm,respectively. The apparent molar absorptivity e was 9.5 × 10^4L · mol^-1 · cm^-1 Beer＇s law was obeyed in the range of 0 to 50 μg/25 mL. Proposed method has been directly applied to determine total rare earths in low-alloyed steel with the RSD of 0. 37%-1. 6%. The determination results are in good agreement with the certified values.

关 键 词：稀土总量 偶氮胂(Ⅲ) 十二烷基磺酸钠 分光光度法 

分 类 号：TG115.33[金属学及工艺—物理冶金]