title: Evaluation of on-line pyrolysis coupled to isotope ratio mass spectrometry for the determination of position-specific (13)C isotope composition of short chain n-alkanes (C6-C12).
abstract: We measured (13)C intramolecular isotopic composition of commercially available short-chain hydrocarbons (n-C6-n-C12) using (13)C-NMR. Results show that the main variation is between the terminal and the sub-terminal C-atom positions. Site-preference (difference in δ(13)C values between terminal and sub-terminal C-atom positions) among all the samples varies between -12.2‰ and +8.4‰. Comparison of these results with those obtained using on-line pyrolysis coupled with GC-C-IRMS show that the thermal cracking of hydrocarbons occurs with a good isotopic fidelity between terminal and sub-terminal C-atom positions of the starting material and the related pyrolysis products (methane and ethylene). On-line pyrolysis coupled with GC-C-IRMS can thus be used for tracing hydrocarbons biogeochemical processes.
authors.affiliation: Earth-Life Science Institute, Tokyo Institute of Technology, Meguro, Tokyo 152-8551, Japan. Electronic address: gilbert.alexis@elsi.jp.
authors.forename: Alexis
authors.initials: A
authors.lastname: Gilbert
authors.affiliation: Department of Environmental Chemistry and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8503, Japan.
authors.forename: Keita
authors.initials: K
authors.lastname: Yamada
authors.affiliation: Earth-Life Science Institute, Tokyo Institute of Technology, Meguro, Tokyo 152-8551, Japan; Department of Environmental Chemistry and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8503, Japan.
authors.forename: Naohiro
authors.initials: N
authors.lastname: Yoshida
mesh_terms: D000473:Alkanes / Q000032:analysis*; D002247:Carbon Isotopes; D013058:Mass Spectrometry; D008697:Methane
chemical_list: D000473:Alkanes; D002247:Carbon Isotopes; D008697:Methane
keywords: Hydrocarbons; Intramolecular isotope distribution; Isotopic (13)C-NMR; On-line pyrolysis