2,4-二氯-6-溴偶氮氟膦与稀土的显色反应及其应用  

Color reaction of 2,4-dichloro-6-bromo fluorophosphonazo with rare earths and its applicaiton

作　　者：俞善辉[1] 江瑜[1] 柯佳鹏[1] 戴聪聪[1] 吴斌才[2] 

机构地区：[1]华东理工大学化学与分子工程学院化学系,上海200237 [2]华东师范大学化学系,上海200062

出　　处：《冶金分析》2012年第8期20-24,共5页Metallurgical Analysis

摘　　要：对显色剂2,4-二氯-6-溴偶氮氟膦(偶氮氟膦-DCB)与稀土元素在微波催化下的显色反应进行了研究。在硝酸及少量吡啶介质中,于40℃的微波水浴中加热催化8min,试剂与稀土元素发生显色反应,形成稳定的蓝色络合物。La、Ce与显色剂的络合比均为1∶3,各稀土元素络合物的最大吸收波长位于632～636nm,表观摩尔吸光系数相近,ε为0.89×105～1.15×105L.mol-1.cm-1。以634nm作为测定波长,改变混合稀土的配分进行试验,结果表明La、Ce、Y的比例对稀土总量测定的影响不显著。采用本方法对岩石等实际样品中稀土总量进行测定,相对标准偏差(RSD,n=5)为2.0%～2.4%,回收率在93%～98%范围。The coloring reactions of chromogenic reagent 2,4-dichloro-6-bromo fluorophosphonazo（fluorophosphonazo-DCB） with rare earth elements under microwave catalysis were been studied.In the nitric acid medium containing a little pyridine,the chromogenic reagent reacted with rare earth elements to form stable blue complexes after heating catalysis in microwave water-bath at 40℃ for 8 minutes.The molar ratios of lanthanum and cerium to reagent were both 1∶3.The maximum absorption wavelengths of rare earth complexes were in range of 632-636 nm.The apparent molar absorptivities（ε） were close and in range of 0.89-1.15×105 L·mol^-1·cm^-1.The proportion of mixed rare earths was tested at measuring wavelength of 634 nm.The results showed that,the proportion of La,Ce and Y had little influence on the determination of total rare earth elements.The proposed method was applied to the determination of total rare earth elements in actual samples such as rock,with the relative standard deviations（RSD,n=5） of 2.0%-2.4%,and the recoveries of 93%-98%.

关 键 词：稀土元素 偶氮氟膦-DCB 微波催化 分光光度法 

分 类 号：O657.32[理学—分析化学]