Araoka Daisuke, Yoshimura Toshihiro
Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology.
Biogeochemistry Program, Japan Agency for Marine-Earth Science and Technology (JAMSTEC).
Anal Sci. 2019 Jul 10;35(7):751-757. doi: 10.2116/analsci.18P509. Epub 2019 Mar 8.
For the rapid, easy, and safe purification of alkali and alkaline-earth elements from rock samples for stable isotope analysis, we developed a semi-automated, high-throughput procedure using borate fusion and an ion chromatography system equipped with a fraction collector. This HF-free procedure for the decomposition of silicate rock samples can be performed in a short time without isotope fractionation; the purification procedure enables the collection of baseline-separated peaks of multiple target elements and the complete removal of interference matrices from reagents and samples. The accuracy of this procedure was verified by confirming the correspondence of stable isotopic values of Li, Mg, Sr (δLi, δMg, δSr) and radiogenic isotopic values of Sr (Sr/Sr) to previously reported values in various geochemical reference materials in which the concentration range of Li was 7.78 - 86.6 ng g, that of Mg was 0.02 - 26.9%, and that of Sr was 178 - 7240 ng g. These results demonstrate that this procedure, which allows for the concurrent multi-isotope analysis of alkali and alkaline-earth elements in the same sample, is applicable to a wide variety of sample types.
为了从岩石样品中快速、简便且安全地纯化碱金属和碱土金属元素以进行稳定同位素分析，我们开发了一种半自动化的高通量方法，该方法采用硼酸盐熔融，并配备了带有馏分收集器的离子色谱系统。这种用于分解硅酸盐岩石样品的无氢氟酸方法可在短时间内完成，且不会产生同位素分馏；纯化过程能够收集多种目标元素的基线分离峰，并完全去除试剂和样品中的干扰基质。通过确认锂、镁、锶的稳定同位素值（δLi、δMg、δSr）以及锶的放射性同位素值（Sr/Sr）与各种地球化学参考物质中先前报道的值一致，验证了该方法的准确性，其中锂的浓度范围为7.78 - 86.6 ng/g，镁的浓度范围为0.02 - 26.9%，锶的浓度范围为178 - 7240 ng/g。这些结果表明，该方法能够对同一样品中的碱金属和碱土金属元素进行同时多同位素分析，适用于多种样品类型。
