2015 Fiscal Year Research-status Report
| Project/Area Number |
15K17774
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
ジルベルト アレキシー 東京工業大学, 地球生命研究所, 助教 (20726955)
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| Project Period (FY) |
2015-04-01 – 2017-03-31
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| Keywords | アイソトプ |
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| Outline of Annual Research Achievements |
We developed and implemented a new system enabling the analysis of 13C/12C content for each carbon atom of propane and butanes (namely “intramolecular isotope composition”).
The apparatus has been used to analyse samples synthesized in the lab, simulating propane formation through abiotic (radical polymerization of CH4) and thermogenic (thermal degradation of organic matter) processes.
The results show that the intramolecular isotope composition of propane are different from the 2 different processes: while abiotic samples show a relatively homogeneous 13C distribution, thermogenic samples show a strong 13C depletion on the terminal C-atom position, consistent with models existing.
Moreover, the signature of synthesized abiotic samples fits perfectly that from abiotic sample from hydrothermal system Hakuba-Happo (Japan) reemphasizing the role of hydrothermal systems in abiotic production.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
Our progress so far fits perfectly the original objectives: developing the apparatus and starting the analysis of amples from different origins.
The apparatus now works very well and is able to determine intramolecular isotope composition of propane and butanes in one single injection, with high sensitivity and high precision (Gilbert et al. 2016, GCA).
We also started the analysis of samples from field (Hakuba-Happo, Japan; Apulian basin, Italy). Some of them will require more purification steps than expected but should be analyzed soon. We are a bit in advance regarding simulating processes reated to natural gas formation/consumption. We already started thermal degradation of organic matter as a proxy for thermogenic gas.
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| Strategy for Future Research Activity |
We shall work on improving the purification steps for some specific natural gas samples, especially those contiaing high amount of carbon dioxide or methane.
We will develop a model based on kinetics and isotope fractionation factors to explain the data otined so far on abiotic samples,m both at the molecular and at the intramoledcular level.
An important step for this project will be to determine the fractionation factors for simulated sinks and sources of natural gas. We already started experiments to simulate abiotic formation. We will make culture experiments aiming at evaluating fractionation factors associated with propane degradation by microorganisms, both un der the presence and in the absence of oxygen.
The above-mentionned steps will help refining the determinants of intramolecular isotope composition of natural gas hydrocarbons, and our understanding ofthe sources and sinks of natural gas on Earth.
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| Causes of Carryover |
I postponed to buy chemicals to conduct an experiment.
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| Expenditure Plan for Carryover Budget |
So I will do so this year FY2016.
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[Journal Article] Position-Specific Isotope Analysis of Xanthines: A 13C Nuclear Magnetic Resonance Method to Determine the 13C Intramolecular Composition at Natural Abundance.2015
Author(s)
D. G. Diomande, E. Martineau, A. Gilbert, P. Nun, A. Murata, K. Yamada, N. Watanabe, I. Tea, R. J. Robins, N. Yoshida, G. S. Remaud
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Journal Title
Analytical Chemistry
Volume: 87
Pages: 6600-6606
DOI
Peer Reviewed / Int'l Joint Research
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