2-(5-溴-2-吡啶偶氮)-5-二甲氨基苯胺激光热透镜光谱法测定痕量铑的研究  

Study on Determination of Rhodium by Laser Thermal Lens Spectrometry Using 2-(5-Bromo-2-pyridylazo)-5-dimethylaminoaniline

作　　者：韩权[1] 霍燕燕[1] 孙丽娟[1] 杨晓慧[1] 翟云会[1] 郝甜甜[1] 

机构地区：[1]西安文理学院化学与化学工程学院,陕西西安710065

出　　处：《分析测试学报》2013年第8期988-992,共5页Journal of Instrumental Analysis

基　　金：陕西省自然科学基础研究计划项目(2010JM2018);西安市科技计划项目(CXY1134WL38)

摘　　要：基于铑(Ⅲ)与2-(5-溴-2-吡啶偶氮)-5-二甲氨基苯胺(5-Br-PADMA)的高灵敏显色反应,建立了激光热透镜光谱法测定痕量铑的新方法。实验表明,在pH 3.6～6.0的HAc-NaAc缓冲介质中,Rh(Ⅲ)与5-Br-PADMA显色形成紫红色铑络合物;继续以1.2 mol/L HClO4酸化后,可转变为另一种具有较高吸收特性的绿蓝色质子化型体,其最大吸收波长位于612 nm处,与所用He-Ne激光器的输出激光波长(632.8 nm)能较好匹配。铑的质量浓度在5～140μg/L范围内与热透镜信号强度呈良好的线性关系,检出限(S/N=3)为1.1μg/L。该方法灵敏度高、选择性好,用于铑炭催化剂中痕量铑的测定,结果满意。A novel method for the determination of trace rhodium by laser thermal lens spectrometry （LTLS） based on the sensitive color reaction between rhodium（ Ⅲ ） and 2-（5-bromo-2-pyridylazo）-5 dimethylaminoaniline（5-Br-PADMA）was established. The experiment results showed that in a media of pH 3.6 - 6. 0 HAc - NaAe buffer solution, rhodium （ Ⅲ ） can react with 5-Br-PADMA to form a violet-red complex. The complex can be changed into another green-blue proton species possessing a high abosorption characteristics in 1.2 mol/L HC104. The optimal concentrations of HC1O4, HCI, H2SO4 or H3PO4 were found to be 0. 6 -3.6 mol . L^-1 for HC104, 0.6 -3.0 mol/L for HC1, 1.2 4.0 mol/L for H2SO4 and 1.8 -4. 5 mol/L for H3PO4, respectively. The maximum absorption wave length was 612 nm which matched well with the output wavelength（632. 8 nm） of He -Ne laser. The analytical curve was linear in the concentration range of 5 - 140 μg/L for rhodium, and the detection limit was 1.1 μg/L. The method, having high sensitivity and good selectivity, was applied in determination of trace rhodium in the rhodium -carbon catalyst with satisfactory results.

关 键 词：2-(5-溴-2-吡啶偶氮)-5-二甲氨基苯胺 激光热透镜光谱法 铑 

分 类 号：O657.3[理学—分析化学] O614.882[理学—化学]