An evaluation of a single-step extraction chromatography separation method for Sm-Nd isotope analysis of micro-samples of silicate rocks by high-sensitivity thermal ionization mass spectrometry.
An evaluation of a single-step extraction chromatography separation method for Sm-Nd isotope analysis of micro-samples of silicate rocks by high-sensitivity thermal ionization mass spectrometry.
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DOI：
10.1016/j.aca.2011.08.036
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发表时间：
2011-11
影响因子：
6.2
通讯作者：
Chaofeng Li;Xian‐Hua Li;Qiu-li Li;Jing-hui Guo;Xianghui Li;Tao Liu
中科院分区：
文献类型：
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作者：
Chaofeng Li;Xian‐Hua Li;Qiu-li Li;Jing-hui Guo;Xianghui Li;Tao Liu
本文提出了硅酸盐岩石中Sm-Nd放射成因同位素体系的一步分离方案。该方法基于Eichrom®LN Spec色谱材料，可直接从复杂基质中分离Sm-Nd，纯度良好，空白水平令人满意，适用于热电离质谱（TIMS）。该技术具有高效（一步Sm-Nd分离）和高灵敏度（NdO+离子束TIMS）的特点，能够快速处理（3- 4小时），程序空白低（<10 pg）和样品非常小（1- 3 mg）。本文介绍了11种国际硅酸盐岩石标准物质的143 Nd/144 Nd比值和Sm-Nd浓度的TIMS重复测量结果，这些标准物质的Sm-Nd含量和体相组成范围很广。在95%的置信水平下，143 Nd/144 Nd同位素比值与推荐值在±0.004%以内，Sm-Nd定量在±2%以内，符合较好。应注意，该方法的不确定性比使用两阶段完全分离然后使用需要大量Nd的Nd+离子束的最先进的常规TIMS可实现的典型精度大约3倍。因此，我们的一步分离和NdO+离子束技术更适合于微量样品的分析。
A single-step separation scheme is presented for Sm–Nd radiogenic isotope system on very small samples (1–3mg) of silicate rock. This method is based on Eichrom®LN Spec chromatographic material and affords a straightforward separation of Sm–Nd from complex matrix with good purity and satisfactory blank levels, suitable for thermal ionization mass spectrometry (TIMS). This technique, characterized by high efficiency (single-step Sm–Nd separation) and high sensitivity (TIMS on NdO+ion beam), is able to process rapidly (3–4h), with low procedure blanks (<10pg) and very small sample (1–3mg). Replicate measurements by TIMS on143Nd/144Nd ratios and Sm–Nd concentrations are presented for eleven international silicate rock reference materials, spanning a wide range of Sm–Nd contents and bulk compositions. The analytical results show a good agreement with recommended values within ±0.004% for the143Nd/144Nd isotopic ratio and ±2% for Sm–Nd quantification at the 95% confidence level. It is noted that the uncertainty of this method is about 3 times larger than typical precision achievable with two-stage full separation followed by state-of-the-art conventional TIMS using Nd+ion beams which require much larger amounts of Nd. Hence, our single-step separation followed by NdO+ion beam technique is preferred to the analysis for microsamples.