Compound-specific stable hydrogen isotope analysis of natural samples in nano-molar levels and its application to earth environmental sciences

使用气相色谱/pyrolysis/isotope比率质量光谱（GC/pyrolysis/IRMS）开发了亚纳米摩尔水平的复合特定氢同位素测量。同位素校准和样品制备，包括无挥发性化合物的衍生化和由硅凝胶色谱法分离的协同化合物也得到了更精确的同位素测量。最后，它可以很容易地确定天然样品的OD值，精确度小于5‰·含有0纳克氢的有机化合物。我们应用了一种确定δD值的方法来确定n-alkanes、n-alkanoid酸、n-alkanols和sterols的生物材料和补充剂，并按顺序讨论其同位素分段机制在不同的生物合成途径中的来源、诊断效应和运输过程。我们还对多环芳香氢化合物的δD测量（C_H_）在碳链中找到不同的δD值在spite of their structural isomers彼此（C_<16>H_<10>）。在添加剂中，吡啶和氟代乙烷在酸性条件下的羟基溶液中的交换，在何处，氢代乙烷在吡啶和水之间交换了更多的容易的相对，在氟代乙烷和水之间。与两个系列（pyrene-series和fluoranthene-series） PAH formation mechanisms in carbonaceous chondrites inferred from carbon isotopic compositions of PAH。最初的这个reserch项目was planned for 4 years （2000-2003 FY）。However， since this project has successfully continued to a new research project as titled "Multi-stable isotope systematics of individual organic compounds in cosmogeochemical samples"，此project for make a final report。

Compound-specific hydrogen isotope measurement has been developed at sub-nano molar level using gas chromatography/pyrolysis/isotope ratio mass spectrometry (GC/pyrolysis/IRMS). Isotopic calibration and sample preparation including derivatization of unvolatile compounds and separation of co-eluted compounds by silica gel chromatography were also established for more precise isotope measurement. Finally, it is successful to determine a OD value of natural samples with precision of less than 5‰ using ・0ng hydrogen-containing organic compound. We applied the established method to determine δD values of n-alkanes, n-alkanoic acids, n-alkanols and sterols of biological materials and sediments, in order to discuss their isotope fractionation mechanisms during different biosynthetic pathways as well as their source, diagenetic effects and transportation processes in sediments. We also conducted the δD measurement of polycyclic aromatic hydrocarbons such as pyrene and fluoranthene in carbonaceous chondrites to find different the δD value in spite of their structural isomers each other (C_<16>H_<10>). In addition, hydrogen isotope exchange of pyrene and fluoranthene occurred in hydrothermal solutions under acidic condition, where where hydrogens have exchanged more easily between pyrene and water relative to between fluoranthene and water. The kinetically different behavior between pyrene and fluoranthene coincides with the two-series (pyrene-series and fluoranthene-series) PAH formation mechanisms in carbonaceous chondrites inferred from carbon isotopic compositions of PAH.Originally this reserch project was planned for 4 years (2000-2003 FY). However, since this project has successfully continued to a new research project as titled "Multi-stable isotope systematics of individual organic compounds in cosmogeochemical samples", this project ended up to make a final report.