Abundances of Sulfur, Selenium, Tellurium, Rhenium and Platinum‐Group Elements in Eighteen Reference Materials by Isotope Dilution Sector‐Field <scp>ICP</scp>‐<scp>MS</scp> and Negative <scp>TIMS</scp>

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.

Section: Resultssupporting

confidence: 90%

A Method to Suppress Isobaric and Polyatomic Interferences for Measurements of Highly Siderophile Elements in Desilicified Geological Samples

Zhou

Tanaka

Yamanaka

et al. 2019

“…The digestion of rock samples has to take into account the volatile behaviour of TABS (Corns et al , König et al , Wang and Becker ), and thus avoid a loss by volatilisation. The use of closed‐cap beakers and low temperature are fundamental (Wang and Becker ). Previous studies indicate that heating the sample up to 80 °C in a closed system results in digestion without any analyte loss.…”

Section: Methodsmentioning

confidence: 99%

“…This technique has also been used by geologists to assess the behaviour of TABS during various geological processes (Pitcairn , Pitcairn et al , Patten et al ). The mass fractions of TABS in geological materials are variable (Hattori et al , Ketris and Yudovich , Henrique‐Pinto et al , Samalens et al ) and, in some cases (especially for Se and Te), very low (König et al , , Wang and Becker , Lissner et al ). The method appears suitable for studying the distribution of TABS in geological materials.…”

mentioning

confidence: 99%

Determination of Te, As, Bi, Sb and Se (TABS) in Geological Reference Materials and GeoPT Proficiency Test Materials by Hydride Generation‐Atomic Fluorescence Spectrometry (HG‐AFS)

Mansur

Barnes

Savard

et al. 2019

The study of Te, As, Bi, Sb and Se (TABS) has increased over the past years due to their use in the development of low‐carbon energy technologies. However, there is a scarcity of mass fraction values of TABS in geological reference materials. This underlines the difficulty in undertaking routine determinations of these elements. The mass fractions of TABS were determined in geological reference materials using hydride generation‐atomic fluorescence spectrometry (HG‐AFS), calibrated with standard solutions. Comparisons with literature values were used to validate the method. Samples from the GeoPT proficiency test were also analysed. For most elements, there are no assigned or even provisional values for many of the GeoPT and reference materials because of the wide range of results reported. For mass fractions above the quantification limit of the method, our results are in good agreement with the median of GeoPT results. Thus, we propose GeoPT median values as informational values for these elements. In contrast, at mass fractions < 0.5 µg g−1 median values of Se from GeoPT are systematically higher than our results. Our Se results are in agreement with the reference materials down to 0.02 µg g−1, which suggest that many of the results for Se reported in GeoPT testing are too high.

“…The intermediate precision was 0.148 ± 14 (2 s , n = 14, t = 6 years), obtained by secondary EM on the Triton TIMS in our laboratory. In addition, the published data of the 187 Os/ 188 Os ratios show a large variation from 0.1320 ± 30 (2SE, Wang and Becker ) to 0.1465 ± 32 (Chu et al . ).…”

Section: Resultsmentioning

confidence: 97%

“…Increasing the sample amounts of WPR‐1 and AGV‐2 should be attempted in the future due to the small size of 0.5 g WPR‐1 and the extremely low Os content of AGV‐2. In summary, WPR‐1 and BIR‐1a exhibit more homogeneity with respect to 187 Os/ 188 Os ratio with test portion masses of 0.5–1 g, and they can serve as ideal geological RMs for Os isotope ratio measurements (Wang and Becker ).…”

Section: Resultsmentioning

confidence: 99%

High‐Precision Measurement of ¹⁸⁷Os/¹⁸⁸Os Isotope Ratios of Nanogram to Picogram Amounts of Os in Geological Samples by N‐TIMS using Faraday Cups Equipped with 10¹³ Ω Amplifiers

Wang

Vollstaedt

2019

N(187Os)/N(188Os) ratios of six geological reference materials were measured using static Faraday cups (FCs) with 1013 Ω amplifiers by N‐TIMS. Our results show that the repeatability precision was 2–3‰ (2 RSD, n = 3), when taking ~ 1 g of BHVO‐2 with 76 pg g−1 of Os mass fraction and ~ 2 g of BCR‐2 with 21 pg g−1 of Os mass fraction for each sample, whether measured by FCs or by secondary electron multiplier. The repeatability precision measured by FCs was 1–0.2‰ (2 RSD, n = 3) when taking ~ 1 g of BIR‐2 with 350 pg g−1 of Os mass fraction, ~ 1 g of WGB‐1 with 493 pg g−1 of Os mass fraction or ~ 0.5 g of WPR‐1 with 13.3 ng g−1 of Os mass fraction for each sample, which is much better than those measured by secondary electron multiplier. Instead, when taking ~ 2 g of AGV‐2 with 4 pg g−1 Os mass fraction, the repeatability precision measured by secondary electron multiplier is 3–4‰ (RSD, n = 3), which is better than those measured by FCs. Of the six reference materials analysed, WPR‐1 and BIR‐1a are the most homogeneous with regard to Os isotopic composition (2 RSD of 0.08% and 0.23%, respectively) when test portion masses are 0.5–1 g.