Eva E Stüeken1, Maria de Castro2, Liliana Krotz3, Christopher Brodie4, Mattia Iammarino5, Guido Giazzi3. 1. School of Earth and Environmental Sciences, University of St Andrews, St Andrews, KY16 9AJ, UK. 2. Thermo Fisher Scientific, Avenida de la Vega, 1, 28108, Alcobendas, Madrid, Spain. 3. Thermo Fisher Scientific, Strada Rivoltana, 20090, Rodano, Milano, Italy. 4. Thermo Fisher Scientific, Hanna Kunath Str. 11, Bremen, 28199, Germany. 5. IIS Curie-Sraffa School, Via Fratelli Zoia, 130, 20153, Milano, Italy.
Abstract
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. This article is protected by copyright. All rights reserved.
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. This article is protected by copyright. All rights reserved.