2B-O1-1020 PDF
有機物の同位体組成：最近の展開
Even after a quarter century has passed after the gas chromatography / combustion / isotope ratio mass spectrometer was commercially available, the investigation of natural abundances of carbon and nitrogen isotopes (13C/12C, 14C/12C, and 15N/14N ratios) in nature is still a niche strategy for well-trained specialists. Nevertheless, in the small community, the isotopic compositions of organic matter have been developed to precisely probe biogeochemical and ecological processes. Both carbon and nitrogen are essential elements of organisms and form various chemical species. These isotopic compositions provide process-related and source information.
In this presentation, I will overview topics and approaches using this technique developed during the last decade or so. For example, compound-specific radiocarbon analysis of individual organic compound in nature is a powerful method for not only determining the synthetic age of the compounds, but also tracing the processes related to the formation, transport, and fate. Nitrogen isotopic composition of individual amino acids has been established as a precise tool for determining the trophic position of the organisms. It depicts prey-predator relationship, a key information for understanding the energy flow in the ecosystem. During the last a few years, this tool has rapidly spread in the communities of not only ecologists but also anthropologists. It has been recognized that these isotopic record is also useful as a forensic evidence by marking the compounds with unique signatures.