Laser absorption spectroscopy of rare and doubly substituted carbon dioxide isotopologues

• Verfasst von: Prokhorov, Ivan [VerfasserIn]
• Verfasst von: Kluge, Tobias [VerfasserIn]
• Verfasst von: Janssen, Christof [VerfasserIn]
• Titel: Laser absorption spectroscopy of rare and doubly substituted carbon dioxide isotopologues
• Verf.angabe: Ivan Prokhorov, Tobias Kluge, Christof Janssen
• E-Jahr: 2019
• Jahr: November 9, 2019
• Umfang: 9 S.
• Fussnoten: Gesehen am 15.04.2020
• Titel Quelle: Enthalten in: Analytical chemistry
• Ort Quelle: Columbus, Ohio : American Chemical Society, 1947
• Jahr Quelle: 2019
• Band/Heft Quelle: 91(2019), 24, Seite 15491-15499
• ISSN Quelle: 1520-6882
• DOI: doi:10.1021/acs.analchem.9b03316
• Datenträger: Online-Ressource
• Sprache: eng
• K10plus-PPN: 1694597555

Abstract

Unambiguous detection of the clumped carbon dioxide isotopologue 13C16O18O with isotope ratio mass spectrometry is difficult due to isobaric interference on m/z = 47. We present an analytical technique based on direct absorption laser spectroscopy for precise, direct and simultaneous detection of all isotopologues involved in the isotope exchange reaction 12C16O2 + 13C16O18O ↔ 12C16O18O + 13C16O2 and of 12C16O17O. The achieved precision of 2 × 10-5 for the 13C16O18O/13C16O2 and 12C16O18O/12C16O2 isotopologue ratios allows the equilibrium constant K of the isotope exchange reaction to be determined with an external reproducibility of better than 2 × 10-5 (1σ) after 9 reference-sample comparisons. Each comparison requires 7 min. The isotopic composition of the pure gas can be simultaneously analyzed with a precision of 0.05‰ (1σ) for δ13C and δ18O and 0.15‰ (1σ) for δ17O. The instrument deploys two interband cascade lasers (ICL) with center wavelengths of 4.3 and 4.4 μm. A custom-built optical cell has been designed for single pass and multi pass optical paths (path length ratio 1:100); it allows simultaneous detection of rare and abundant isotopologues. The setup is capable to analyze pure CO2 samples of ∼100 μmol.