A reliable analytical procedure to determine the carbon isotopic signature of CO<sub>2</sub>-bearing COH fluids generated in petrological experiments
<p>The ratio of stable carbon isotopes, <span class="inline-formula"><i>δ</i><sup>13</sup></span>C, serves as a fundamental tracer for geological processes. Experiments aiming to replicate isotopic exchange between carbon reservoirs encounter sign...
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Copernicus Publications
2025-01-01
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| Series: | European Journal of Mineralogy |
| Online Access: | https://ejm.copernicus.org/articles/37/25/2025/ejm-37-25-2025.pdf |
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| author | L. Toffolo L. Minopoli E. Ferrari S. Tumiati |
| author_facet | L. Toffolo L. Minopoli E. Ferrari S. Tumiati |
| author_sort | L. Toffolo |
| collection | DOAJ |
| description | <p>The ratio of stable carbon isotopes, <span class="inline-formula"><i>δ</i><sup>13</sup></span>C, serves as a fundamental tracer for geological processes. Experiments aiming to replicate isotopic exchange between carbon reservoirs encounter significant analytical challenges due to the limited sample size and issues related to sampling, particularly when dealing with volatile species. Here we present a novel methodology that integrates a capsule-piercing device, a quadrupole mass spectrometer (QMS), and isotopic ratio mass spectrometry (IRMS) to measure the CO<span class="inline-formula"><sub>2</sub></span> concentration and natural-like <span class="inline-formula"><i>δ</i><sup>13</sup></span>C ratio of CO<span class="inline-formula"><sub>2</sub></span> in the volatile COH phase generated in petrological experiments. To validate the technique, we first analyze the COH fluid resulting from the thermal decomposition of 1 mg of anhydrous oxalic acid. The optimal values of the carrier gas flow in the QMS, sampling times, and chromatography column temperature for IRMS are determined. The high degree of similarity, within acceptable errors, observed in both compositional and isotopic analyses indicates a robust reproducibility, minimally affected by contamination and fractionation effects during sampling. We also show that this methodology can be applied for estimating the <span class="inline-formula"><i>δ</i><sup>13</sup></span>C of CO<span class="inline-formula"><sub>2</sub></span> produced from high-pressure, high-temperature, redox-buffered piston–cylinder experiments. This offers a multitude of opportunities in designing experiments focused on determining isotopic fractionation models for geological processes that involve, but are not restricted to, CO<span class="inline-formula"><sub>2</sub></span>-bearing COH fluids.</p> |
| format | Article |
| id | doaj-art-37fa0762984647228f6eea291faf44b9 |
| institution | Kabale University |
| issn | 0935-1221 1617-4011 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | European Journal of Mineralogy |
| spelling | doaj-art-37fa0762984647228f6eea291faf44b92025-01-17T11:32:13ZengCopernicus PublicationsEuropean Journal of Mineralogy0935-12211617-40112025-01-0137253710.5194/ejm-37-25-2025A reliable analytical procedure to determine the carbon isotopic signature of CO<sub>2</sub>-bearing COH fluids generated in petrological experimentsL. Toffolo0L. Minopoli1E. Ferrari2S. Tumiati3Dipartimento di Scienze della Terra “Ardito Desio” (DiSTAD), University of Milan, Milan, 20122, ItalyDipartimento di Scienze della Terra “Ardito Desio” (DiSTAD), University of Milan, Milan, 20122, ItalyDipartimento di Scienze della Terra “Ardito Desio” (DiSTAD), University of Milan, Milan, 20122, ItalyDipartimento di Scienze della Terra “Ardito Desio” (DiSTAD), University of Milan, Milan, 20122, Italy<p>The ratio of stable carbon isotopes, <span class="inline-formula"><i>δ</i><sup>13</sup></span>C, serves as a fundamental tracer for geological processes. Experiments aiming to replicate isotopic exchange between carbon reservoirs encounter significant analytical challenges due to the limited sample size and issues related to sampling, particularly when dealing with volatile species. Here we present a novel methodology that integrates a capsule-piercing device, a quadrupole mass spectrometer (QMS), and isotopic ratio mass spectrometry (IRMS) to measure the CO<span class="inline-formula"><sub>2</sub></span> concentration and natural-like <span class="inline-formula"><i>δ</i><sup>13</sup></span>C ratio of CO<span class="inline-formula"><sub>2</sub></span> in the volatile COH phase generated in petrological experiments. To validate the technique, we first analyze the COH fluid resulting from the thermal decomposition of 1 mg of anhydrous oxalic acid. The optimal values of the carrier gas flow in the QMS, sampling times, and chromatography column temperature for IRMS are determined. The high degree of similarity, within acceptable errors, observed in both compositional and isotopic analyses indicates a robust reproducibility, minimally affected by contamination and fractionation effects during sampling. We also show that this methodology can be applied for estimating the <span class="inline-formula"><i>δ</i><sup>13</sup></span>C of CO<span class="inline-formula"><sub>2</sub></span> produced from high-pressure, high-temperature, redox-buffered piston–cylinder experiments. This offers a multitude of opportunities in designing experiments focused on determining isotopic fractionation models for geological processes that involve, but are not restricted to, CO<span class="inline-formula"><sub>2</sub></span>-bearing COH fluids.</p>https://ejm.copernicus.org/articles/37/25/2025/ejm-37-25-2025.pdf |
| spellingShingle | L. Toffolo L. Minopoli E. Ferrari S. Tumiati A reliable analytical procedure to determine the carbon isotopic signature of CO<sub>2</sub>-bearing COH fluids generated in petrological experiments European Journal of Mineralogy |
| title | A reliable analytical procedure to determine the carbon isotopic signature of CO<sub>2</sub>-bearing COH fluids generated in petrological experiments |
| title_full | A reliable analytical procedure to determine the carbon isotopic signature of CO<sub>2</sub>-bearing COH fluids generated in petrological experiments |
| title_fullStr | A reliable analytical procedure to determine the carbon isotopic signature of CO<sub>2</sub>-bearing COH fluids generated in petrological experiments |
| title_full_unstemmed | A reliable analytical procedure to determine the carbon isotopic signature of CO<sub>2</sub>-bearing COH fluids generated in petrological experiments |
| title_short | A reliable analytical procedure to determine the carbon isotopic signature of CO<sub>2</sub>-bearing COH fluids generated in petrological experiments |
| title_sort | reliable analytical procedure to determine the carbon isotopic signature of co sub 2 sub bearing coh fluids generated in petrological experiments |
| url | https://ejm.copernicus.org/articles/37/25/2025/ejm-37-25-2025.pdf |
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