Direct High-Precision Measurements of the (87)Sr/(86)Sr Isotope Ratio in Natural Water without Chemical Separation Using Thermal Ionization Mass Spectrometry Equipped with 10(12) Ω Resistors.
Direct High-Precision Measurements of the (87)Sr/(86)Sr Isotope Ratio in Natural Water without Chemical Separation Using Thermal Ionization Mass Spectrometry Equipped with 10(12) Ω Resistors.
复制标题
DOI：
10.1021/acs.analchem.5b01627
复制
发表时间：
2015-07
影响因子：
7.4
通讯作者：
Chaofeng Li;Jing-hui Guo;Zhuyin Chu;Lianjun Feng;Xuan‐Ce Wang
中科院分区：
文献类型：
--
作者：
Chaofeng Li;Jing-hui Guo;Zhuyin Chu;Lianjun Feng;Xuan‐Ce Wang
热电离质谱法（TIMS）可以非常精确地测定天然水样中的Sr同位素比率。传统的化学分离方法是利用阳离子交换树脂从天然水中获得高纯度的锶，这使得样品制备非常耗时。在这项研究中，我们提出了一种快速而精确的方法，用于直接测定天然水的Sr同位素比率，使用配备两个10（12）Ω电阻放大器的TIMS。为了消除（87）Rb等压干扰，使用Re带作为长丝，在抑制Rb（+）发射方面比W带有明显的优势，基于系统地检查了一系列NIST SRM987标准掺杂不同数量的Rb使用Re和W带。为了验证方法的适用性，在华北和华南地区收集了22个自然水样，包括不同的水类型（雨、雪、河流、湖泊和饮用水），并分析了Sr含量变化范围较大（2.54-922.8 ppb）。分析结果表明，该方法精密度为0.003 ~ 0.005%，RSE为2，并通过对同一水进行化学分离和不进行化学分离的对比分析进一步验证了该方法的有效性。该方法简单，快速，消除了样品制备时间，并防止在复杂的样品制备过程中潜在的污染。因此，可以充分利用TIMS固有的高样品吞吐量。
Thermal ionization mass spectrometry (TIMS) allows excellent precision for determining Sr isotope ratios in natural water samples. Traditionally, a chemical separation procedure using cation exchange resin has been employed to obtain a high purity Sr fraction from natural water, which makes sample preparation time-consuming. In this study, we present a rapid and precise method for the direct determination of the Sr isotope ratio of natural water using TIMS equipped with amplifiers with two 10(12) Ω resistors. To eliminate the (87)Rb isobaric interference, Re ribbons are used as filaments, providing a significant advantage over W ribbons in the inhibition of Rb(+) emission, based on systematically examining a series of NIST SRM987 standard doping with various amounts of Rb using Re and W ribbons. To validate the applicability of our method, twenty-two natural water samples, including different water types (rain, snow, river, lake and drinking water), that show a large range in Sr content variations (2.54-922.8 ppb), were collected and analyzed from North and South China. Analytical results show good precision (0.003-0.005%, 2 RSE) and the method was further validated by comparative analysis of the same water with and without chemical separation. The method is simple and rapid, eliminates sample preparation time, and prevents potential contamination during complicated sample-preparation procedures. Therefore, a high sample throughput inherent to the TIMS can be fully utilized.