地学前缘 ›› 2011, Vol. 18 ›› Issue (2): 304-314.

• 论文 • 上一篇    下一篇

MC-ICP-MS高精度测定Li同位素分析方法

苏嫒娜,田世洪,李真真,侯增谦,侯可军,胡文洁,高延光,杨丹,李延河,杨竹森   

  1. 1. 中国地质科学院 矿产资源研究所， 国土资源部成矿作用与资源评价重点实验室， 北京 100037
    2. 东华理工大学， 江西  抚州 344000
    3. 昆明理工大学， 云南 昆明 650093
    4. 中国地质科学院 地质研究所， 北京 100037
    5. 中国地质调查局， 北京 100037
  • 收稿日期:2010-01-23 修回日期:2010-12-15 出版日期:2011-03-15 发布日期:2011-04-15
  • 作者简介:苏嫒娜（1984—），女，硕士研究生，地球化学专业，主要从事同位素地球化学研究工作。E-ail: aina.su@163.com
  • 基金资助:

    国家自然科学基金面上项目（40973013）；公益性行业科研专项(201011027)；国土资源大调查项目（1212011120298,12120108160）；中央级公益性科研院所基本科研业务费专项（K0802）；中国地质科学院实验室基金项目（2009SYS06）

Highprecision measurement of lithium isotopes using MCICPMS.

  1. 1. Key Laboratory of Metallogeny and Mineral Assessment, MLR, Institute of Mineral Resource, Chinese Academy of Geological Sciences, Beijing 100037, China
    2. East China Institute of Technology, Fuzhou 344000, China
    3. Kunming University of Science and Technology, Kunming 650093, China
    4. Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China
    5. China Geological Survey, Beijing 100037, China
  • Received:2010-01-23 Revised:2010-12-15 Online:2011-03-15 Published:2011-04-15

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摘要：

以不同浓度Li元素标准样品和K、Ca、Na、Mg、Fe单元素标准样品的混合溶液为研究对象，采用3根阳离子交换树脂（AG 50WX8，200~400目）填充的聚丙烯交换柱和石英交换柱对Li进行分离富集，淋洗液分别为28 mol/L HCl、015 mol/L HCl以及05 mol/L HCl 30%乙醇，淋洗液体积小，仅为38 mL。分离回收率高，均大于976%。国际标样AGV2（相对于IRMM016）、BHVO2（相对于IRMM016）和IRMM016（相对于LSVEC）的δ7Li值分别为(513±094)‰(2σ,n=10)、(408±060)‰(2σ,n=4)和(0038±073)‰(2σ,n=10)，与前人分析结果吻合，分析精度与国际同类实验室水平相当。并对比了马里兰大学同位素实验室和笔者实验室对同种岩石矿物样品的分析结果，在误差范围内具有很好的一致性。此外，对美国地质调查局提供的准标样NKT1霞石岩（相对于IRMM016）给出了定值，δ7Li值为(871±046)‰(2σ,n=4)。因此，本方法可用于测定天然样品的Li同位素组成。

关键词:  , Li同位素分析方法, 国际标样AGV2、BHVO2、IRMM016, MCICPMS

Abstract:

 A highyield lithium separation technique for rock samples has been established together with precise Li isotope analysis by MCICPMS. The solutions with different concentration of lithium element standard reference materials and single element standard samples of potassium, calcium, sodium, magnesium and iron were used to evaluate the analytical methods applied. Three separate stages of ionexchange chromatography were carried out using organic cation exchange resin (AG 50WX8,200—400 mesh). Lithium was enriched in different eluants for the different stages. 28 mol/L HCl, 015 mol/L HCl and 05 mol/L HCl in 30% ethanol were used for the different three stages. Two kinds of columns which are made of polypropylene for the first and second stages and quartz for the third stage were used, which is different from those used abroad. Total reagent volume for the entire chemical process was reduced to 38 mL for the rock samples and the recovery is more than 976%. The precision of this technique is conservatively estimated to be ±060‰—094‰ (2σ population), which is similar to the precision of other methods used abroad. The δ7Li value (7Li/6Li relative to the IRMM016 standard) determined for AGV2 is 513‰. The δ7Li values determined for BHVO2 (7Li/6Li relative to the IRMM016 standard) and IRMM016 (7Li/6Li relative to the LSVEC standard) are 408‰ and 0038‰, respectively. In addition, the results for the same kinds of samples analyzed by my lab are the same as those by isotope lab of Maryland University. All the analytical results are consistent with those reported by others. Moreover, the δ7Li value (7Li/6Li relative to the IRMM016 standard) determined for substandard NKT1 nephelinite obtained from the United States Geological Survey (USGS) is 871‰ and its precision is ±046‰. According to the experiments, it is concluded that this proposed procedure is a suitable method for determining the lithium isotopic composition of natural samples.

Key words:  lithium isotope analytical method, international standard samples AGV2, BHVO2, IRMM016, multicollector magnetic sector inductively coupled plasmasource mass spectrometer

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