碳氮稳定同位素在地球科学、生命科学、环境科学、农业科学等各个领域有着广泛的应用。由于同时含有碳氮原子的氨基酸是蛋白质的构成单位,参与机体的代谢,具有重要的生物功能,因此在利用同位素示踪研究中,氨基酸有其重要的研究价值。本...碳氮稳定同位素在地球科学、生命科学、环境科学、农业科学等各个领域有着广泛的应用。由于同时含有碳氮原子的氨基酸是蛋白质的构成单位,参与机体的代谢,具有重要的生物功能,因此在利用同位素示踪研究中,氨基酸有其重要的研究价值。本文仅就利用气相色谱-燃烧-同位素比值质谱仪(gas chromatography-combustion-isotope ratio mass spectrometry,GC-C-IRMS)分析氨基酸的碳氮同位素比值的衍生化方法进行总结,比较各种方法的优缺点,以期对于分析氨基酸的碳氮同位素比值的研究工作提供有益的帮助。展开更多
In this study, biomarkers, together with stable carbon(δ13 C) and hydrogen(δD) isotopic compositions of n-alkanes have been examined in a suite of condensates collected from the East China Sea Shelf Basin(ECSSB) in ...In this study, biomarkers, together with stable carbon(δ13 C) and hydrogen(δD) isotopic compositions of n-alkanes have been examined in a suite of condensates collected from the East China Sea Shelf Basin(ECSSB) in order to delineate their source organic matter input, depositional conditions and evaluate their thermal maturity. Previously, GC-MS analyses have shown that all the condensates are formed in oxidizing environment with terrestrial plants as their main source input. No significant differences were apparent for biomarker parameters, likely due to the low biomarker content and high maturity of these condensates. Conventional GC-MS analysis however, may provides limited information on the sources and thermal maturity of complex mixtures due to insufficient component resolution. In the current study, we used comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry(GC×GC-TOFMS) to increase the chromatographic resolution. Compounds such as alkyl cyclohexanes, alkyl cyclopentanes and diamondoids, which can be difficult to identify using conventional GC-MS analysis, were successfully identified using GC×GC-TOFMS. From our analyses we propose two possibly unreported indicators, including one maturity indicator(C5--cyclohexane/C5+-cyclohexane) and one oxidation-reduction environment indicator(alkyl-cyclohexane/alkyl-cyclopentane). Multiple petroleum charging events were proposed as an explanation for the maturity indicators indexes discrepancy between methyl-phenanthrene index(MPI) and methyl-adamantane index(MDI). In addition, the stable isotopic results show that condensates from the Paleogene have significantly higher positive δ13 C values of individual n-alkanes than the Neogene samples. Based on δD values, the samples can be divided into two groups, the differences between which are likely to be attributed to different biosynthetic precursors. Variation within each group can likely be attributed to vaporization.展开更多
The carbon isotopic composition of individual light hydrocarbons generated from source rocks that had been pyrolysed in vacuum glass tube were determined by using the GC-IRMS techniques. The results indicate that abun...The carbon isotopic composition of individual light hydrocarbons generated from source rocks that had been pyrolysed in vacuum glass tube were determined by using the GC-IRMS techniques. The results indicate that abundant CO2 in the pyrolysates has a remarkable effect on the determination of CH4δ13C. Running cryogenically with an initial temperature of -40℃ can effectively eliminate the effect. In addition, it conduces to measuring the δ13C of C2+ hydrocarbons by increasing the injection volume and/or absorbing CO2 with the solution of sodium hydroxide. The above measures will help to get the carbon isotopic composition of C1-C7 components, which is of great significance for gas/source rock correlation and for study on the genesis of natural gas.展开更多
文摘碳氮稳定同位素在地球科学、生命科学、环境科学、农业科学等各个领域有着广泛的应用。由于同时含有碳氮原子的氨基酸是蛋白质的构成单位,参与机体的代谢,具有重要的生物功能,因此在利用同位素示踪研究中,氨基酸有其重要的研究价值。本文仅就利用气相色谱-燃烧-同位素比值质谱仪(gas chromatography-combustion-isotope ratio mass spectrometry,GC-C-IRMS)分析氨基酸的碳氮同位素比值的衍生化方法进行总结,比较各种方法的优缺点,以期对于分析氨基酸的碳氮同位素比值的研究工作提供有益的帮助。
基金sponsored by the National Science and Technology Major Project of China (Nos. 2016ZX05024-002003, 2016ZX05027-001-005)
文摘In this study, biomarkers, together with stable carbon(δ13 C) and hydrogen(δD) isotopic compositions of n-alkanes have been examined in a suite of condensates collected from the East China Sea Shelf Basin(ECSSB) in order to delineate their source organic matter input, depositional conditions and evaluate their thermal maturity. Previously, GC-MS analyses have shown that all the condensates are formed in oxidizing environment with terrestrial plants as their main source input. No significant differences were apparent for biomarker parameters, likely due to the low biomarker content and high maturity of these condensates. Conventional GC-MS analysis however, may provides limited information on the sources and thermal maturity of complex mixtures due to insufficient component resolution. In the current study, we used comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry(GC×GC-TOFMS) to increase the chromatographic resolution. Compounds such as alkyl cyclohexanes, alkyl cyclopentanes and diamondoids, which can be difficult to identify using conventional GC-MS analysis, were successfully identified using GC×GC-TOFMS. From our analyses we propose two possibly unreported indicators, including one maturity indicator(C5--cyclohexane/C5+-cyclohexane) and one oxidation-reduction environment indicator(alkyl-cyclohexane/alkyl-cyclopentane). Multiple petroleum charging events were proposed as an explanation for the maturity indicators indexes discrepancy between methyl-phenanthrene index(MPI) and methyl-adamantane index(MDI). In addition, the stable isotopic results show that condensates from the Paleogene have significantly higher positive δ13 C values of individual n-alkanes than the Neogene samples. Based on δD values, the samples can be divided into two groups, the differences between which are likely to be attributed to different biosynthetic precursors. Variation within each group can likely be attributed to vaporization.
文摘The carbon isotopic composition of individual light hydrocarbons generated from source rocks that had been pyrolysed in vacuum glass tube were determined by using the GC-IRMS techniques. The results indicate that abundant CO2 in the pyrolysates has a remarkable effect on the determination of CH4δ13C. Running cryogenically with an initial temperature of -40℃ can effectively eliminate the effect. In addition, it conduces to measuring the δ13C of C2+ hydrocarbons by increasing the injection volume and/or absorbing CO2 with the solution of sodium hydroxide. The above measures will help to get the carbon isotopic composition of C1-C7 components, which is of great significance for gas/source rock correlation and for study on the genesis of natural gas.
