RATIONALE Elemental abundances and isotopic ratios of carbon, nitrogen, sulfur and hydrogen have become important tools for reconstructing the evolution of Earth and life over geologic timescales, requiring accurate and precise analytical methods with high sample throughput. However, these measurements may require separate instruments for each task, such as an elemental analyzer (EA) with a thermal conductivity detector (TCD) for elemental abundances and an EA interfaced with a mass spectrometer for isotopic ratios. METHODS To improve sample throughput and laboratory up-time, we developed a switch that allows converting an EA IsoLinkTM system from a standalone mode using only a TCD to a mode for isotope ratio mass spectrometry (IRMS) within minutes. This permits accurate measurements of elemental abundances and isotopic ratios with high throughput and lower cost. We validated this method with six shale standards from the US Geological Survey (USGS) and compared our abundance data with those from another laboratory. RESULTS Our results show that (a) abundance data agree well between the different laboratories and setups; (b) reproducible isotopic data can be obtained before and after the switch-over from EA standalone mode; and (c) the USGS rock standards cover a wide range in CHNS abundances and CNS isotopes, making them ideal reference materials for a range of geochemical studies. CONCLUSIONS This ideal analytical setup has the advantage that abundance measurements can be performed to determine optimal sample amounts for later isotopic analyses, ensuring higher data quality. Our setup eliminates the need for a separate EA while freeing up the mass spectrometer for other tasks during abundance measurements.

中文翻译：

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通过元素分析仪-同位素比率质谱法在CHNS丰度和CNS同位素比率分析之间的最佳转换：应用于六种地质参考物质。

理据碳，氮，硫和氢的元素丰度和同位素比已经成为重建地球和生命地质时期生命演化的重要工具，需要具有高样品通量的准确，精确的分析方法。但是，这些测量可能需要针对每个任务的单独仪器，例如具有用于元素丰度的热导检测器（TCD）的元素分析仪（EA）和用于同位素比率的与质谱仪连接的EA。方法为了提高样品通量和实验室正常运行时间，我们开发了一种开关，可在几分钟内将EA IsoLinkTM系统从仅使用TCD的独立模式转换为同位素比质谱（IRMS）模式。这样可以以高通量和较低的成本准确测量元素丰度和同位素比。我们用美国地质调查局（USGS）的六种页岩标准物验证了该方法，并将我们的丰度数据与其他实验室的数据进行了比较。结果我们的结果表明：（a）不同实验室和机构之间的丰度数据吻合良好；（b）从EA独立模式切换之前和之后均可获得可再现的同位素数据；（c）USGS岩石标准涵盖了CHNS丰度和CNS同位素的广泛范围，使其成为进行一系列地球化学研究的理想参考材料。结论这种理想的分析设置的优点是可以进行丰度测量以确定最佳的样品量，以用于以后的同位素分析，从而确保更高的数据质量。