A Method to Suppress Isobaric and Polyatomic Interferences for Measurements of Highly Siderophile Elements in Desilicified Geological Samples
A Method to Suppress Isobaric and Polyatomic Interferences for Measurements of Highly Siderophile Elements in Desilicified Geological Samples
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DOI：
10.1111/ggr.12280
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发表时间：
2019-03
影响因子：
3.8
通讯作者：
Xiaoyu Zhou;R. Tanaka;M. Yamanaka;C. Sakaguchi;E. Nakamura
中科院分区：
文献类型：
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作者：
Xiaoyu Zhou;R. Tanaka;M. Yamanaka;C. Sakaguchi;E. Nakamura
在升高的温度和压力下使用反王水进行样品分解（例如，Carius管或高压灰化器）是从地质样品中提取高度亲铁元素（HSE：Ru、Rh、Pd、Re、Os、Ir、Pt和Au）的最常用方法。最近，人们已经认识到，额外的HF脱硅是必要的，以更好地回收HSE，可能包含在镁铁质样品中的硅酸盐或氧化物矿物中，其不能单独通过反王水溶解。然而，当将常规离子交换纯化程序应用于脱硅样品时，洗脱液中干扰元素的丰度往往会增加。在这项研究中，我们开发了一种改进的纯化方法来测定脱硅样品中的HSEs。这种方法能够减少同量异位素和多原子干扰的比例，相对于HSE同位素质量的测量强度，小于几百百万分之一。此外，总的程序空白与传统方法相当或低于传统方法。因此，该方法允许在镁铁质和超镁铁质地质样品中进行准确和精确的HSE测量，而不需要干扰校正。此外，对于脱硅样品，避免了干扰元素增加的问题，例如Zr对Pd和Cr对Ru。
Sample decomposition using inverse aqua regia at elevated temperatures and pressures (e.g., Carius tube or high‐pressure asher) is the most common method used to extract highly siderophile elements (HSEs: Ru, Rh, Pd, Re, Os, Ir, Pt and Au) from geological samples. Recently, it has been recognised that additional HF desilicification is necessary to better recover HSEs, potentially contained within silicate or oxide minerals in mafic samples, which cannot be dissolved solely by inverse aqua regia. However, the abundance of interfering elements tends to increase in the eluent when conventional ion‐exchange purification procedures are applied to desilicified samples. In this study, we developed an improved purification method to determine HSEs in desilicified samples. This method enables the reduction of the ratios of isobaric and polyatomic interferences, relative to the measured intensities of HSE isotope masses, to less than a few hundred parts per million. Furthermore, the total procedural blanks are either comparable to or lower than conventional methods. Thus, this method allows accurate and precise HSE measurements in mafic and ultramafic geological samples, without the need for interference corrections. Moreover, the problem of increased interfering elements, such as Zr for Pd and Cr for Ru, is circumvented for the desilicified samples.