Rhenium (Re) is a trace element whose redox chemistry makes it an ideal candidate to trace a range of geochemical processes. In particular, fractionation of its isotopes ¹⁸⁷Re (62.6% abundance) and ¹⁸⁵Re (37.4%) may be used to improve our understanding of redox reactions during weathering, both in the modern day and in geological archives. Published methods for measurement of Re isotopic composition are limited by the requirements of Re mass to reach a desirable precision, making the analysis of many geological materials unfeasible at present. Here we develop new methods which allow us to measure Re isotope ratios (reported as δ¹⁸⁷Re) with improved precision: ±0.10‰ (2σ) for a mass of Re of ∼1 ng to ±0.03‰ (2σ) for a mass of Re of >10 ng. This is possible due to the combination of a modified column chemistry procedure and the use of 10¹³ Ω amplifiers for measurement via multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS). For river water samples (with Re concentrations typically ∼10⁻¹² g g⁻¹) we design a field-based pre-concentration of Re that can be used with large volumes of filtered water (5–20 L) shortly after sample collection to provide abundant Re for isotope analysis. As a result of these developments we provide new measurements of δ¹⁸⁷Re in standards reference materials (δ¹⁸⁷Re values range from −0.06 ± 0.07‰ to +0.19 ± 0.05‰) and a seawater standard (δ¹⁸⁷Re = +0.10 ± 0.04‰), providing impetus for further exploration of the Re isotope system.

中文翻译：

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低丰度样品中rh同位素组成的测量

hen（Re）是一种微量元素，其氧化还原化学使其成为追踪一系列地球化学过程的理想候选者。特别是，在现代和地质档案中，其同位素¹⁸⁷ Re（62.6％丰度）和¹⁸⁵ Re（37.4％）同位素的分馏可用于增进我们对风化过程中氧化还原反应的了解。稀土元素质量的要求限制了已发表的稀土同位素组成的测量方法，以达到理想的精度，目前对许多地质材料的分析是不可行的。在这里，我们开发新的方法，其允许我们能够测量重同位素比率（报告为δ ¹⁸⁷ Re）的具有改进的精度：±0.10‰（2 σ为〜1 1ng至±0.03‰（2的Re的质量）σ），Re的质量> 10 ng。这是可能的，因为修改的列化学过程的组合和使用的10个¹³ Ω放大器，用于测量经由多接收电感耦合等离子体质谱法（MC-ICP-MS）。对于河水样品（Re浓度通常约为10 ^-12 gg ^-1），我们设计了基于现场的Re预浓缩，可在样品收集后不久将其与大量过滤水（5-20​​ L）一起使用，以提供丰富的Re用于同位素分析。作为这些发展的结果，我们提供的δ新的测量¹⁸⁷再在标准参考材料（δ ^187个回复值的范围从-0.06±0.07‰至0.19±0.05‰）和海水标准（δ¹⁸⁷ Re = +0.10±0.04‰），为进一步探索Re同位素系统提供了动力。