电感耦合等离子体质谱(ICP-MS)法测定地质样品中重稀土元素和钍、铀

Determination of Heavy Rare Earth Element,Th and U in Geological Samples by Inductively Coupled Plasma-Mass Spectrometry

对电感耦合等离子体质谱（ICP-MS）法同时测定地质样品中重稀土元素和钍、铀的前处理方法做了改进。采取酸溶法和碱熔法结合，先用硝酸、盐酸、氢氟酸和高氯酸溶样，用盐酸（1＋1）提取，再过滤，滤渣及滤纸灰化后再碱熔，最后用电感耦合等离子体质谱（ICP-Ms）法测定重稀土元素和钍、铀的含量。增加称样量以保证样品更具代表性。克服了酸溶法分解不完全导致测定结果偏低和碱熔法引入太多盐分堵塞ICP-MS矩管和雾化器的两大弊端。方法经国家一级标准物质验证，测定值与标准值基本一致，方法相对标准偏差（RSD）为1．0％～5．6％，符合地质样品分析规范要求。钇、铽、镝、钬、铒、铥、镱、镥和钍、铀的方法定量限分别为0．19、0．017、0．032、0．008、0．046、0．004、0．032、0．005、0．024、0．069μg／g。

A sample digestion method for simultaneous determination of heavy rare earth elements, Th and U in geological samples by inductively coupled plasma-mass spectrometry （ICP-MS） was improved. Acid dissolution method together with alkaline dissolution method were used to prepare sample solution. The samples were first dissolved with nitric acid, hydrochloric acid, hydrofluoric acid and perchloric acid medium. They were then extracted by hydrochloric acid （1 ±1） and the solutions were prepared by filtration. After the residue and filter paper were ashed, the samples were treated with alkali dissolution. The final solutions were used for the determination of heavy rare earth element, Th and U by ICP-MS. Increasing sample amount made the sample more representative. Two disadvantages, including lower measurement results obtained by acid dissolution due to the incompletion of sample digestion and the clogging of torch and the nebulizer of ICP-MS by the excessive salts in the process of alkaline dissolution, were overcome in this work. The method has been validated by determination o{ these elements in national standard reference materials and the results are in good agreement with the certified values with RSD of 1.0%-5.6%. The quantification limits for Y, Tb, Dy, Ho, Er, Tm, Yb, Lu, Th and U were 0.19, 0. 017, 0. 032, 0. 008, 0. 046, 0. 004, 0. 032, 0. 005, 0. 024, 0. 069 μg/g, respectively.