Precise Measurements of 12CH2D2 by Tunable Infrared Laser Direct Absorption Spectroscopy
| Autor: | Joanne H. Shorter, Colin M. Western, Shuhei Ono, David D. Nelson, J. Barry McManus, David T. Wang, Michael J. Formolo, Christoph Dyroff, Yenny González |
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| Rok vydání: | 2019 |
| Předmět: |
Thermal equilibrium
Absorption spectroscopy Chemistry 010401 analytical chemistry Far-infrared laser Analytical chemistry 010402 general chemistry Laser 01 natural sciences Methane 0104 chemical sciences Analytical Chemistry law.invention chemistry.chemical_compound Deuterium law Isotopologue Optical path length |
| Zdroj: | Gonzalez, Y, Nelson, D D, Shorter, J H, McManus, J B, Dyroff, C, Formolo, M, Wang, D T, Western, C M & Ono, S 2019, ' Precise Measurements of 12 CH 2 D 2 by Tunable Infrared Laser Direct Absorption Spectroscopy ', Analytical Chemistry, vol. 91, 23, pp. 14967-14974 . https://doi.org/10.1021/acs.analchem.9b03412 |
| ISSN: | 1520-6882 0003-2700 |
| DOI: | 10.1021/acs.analchem.9b03412 |
| Popis: | We present precise measurements of doubly deuterated methane (12CH2D2) in natural methane samples using tunable infrared laser direct absorption spectroscopy (TILDAS). Using a 413 m optical path length astigmatic Herriott cell and two quantum cascade lasers (QCLs) scanning the spectral regions of 1090.46 ± 0.1 and 1200.23 ± 0.1 cm-1, the instrument simultaneously measures the five main isotopologues of methane. The ratios 13CH3D/12CH4 and 12CH2D2/12CH4 are measured at 0.01‰ and 0.5‰ (1σ) instrumental precision, respectively. The instrumental accuracy was assessed by measuring a series of methane gases with a range of δ13C and δD values but with the abundances of all isotopologues driven to thermal equilibrium at 250 °C. The estimated accuracy of Δ12CH2D2 is 1‰ (1σ) on the basis of the results of the heated methane samples. This new TILDAS instrument provides a simple and rapid technique to explore the sources of methane in the environment. |
| Databáze: | OpenAIRE |
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