The molecular compositions and com- pound-specific carbon isotope compositions of indi- vidual long-chain n-alkanes of atmospheric aerosols collected during two severe Asian dust episodes in Qingdao in spring of 2002 ...The molecular compositions and com- pound-specific carbon isotope compositions of indi- vidual long-chain n-alkanes of atmospheric aerosols collected during two severe Asian dust episodes in Qingdao in spring of 2002 were analyzed using gas chromatography/mass spectrometry (GC/MS) and gas chromatography/isotope ratio mass spectrometry (GC/IRMS). Typical plant wax n-alkanes (C29 and C31) had lower δ 13C values than those from anthropo- genic (engine exhaust) sources (C21―C23). The av- erage δ 13C value of plant wax n-alkane C29 in non-dust episode periods was -30.5‰ (?30.3‰― ?31.9‰), while -31.3‰ (?31.1‰―?31.5‰) in dust episode periods; for C31, it was ?31.4‰ (?31.1‰― ?33.0‰) in non-dust episode periods, and ?31.7‰ (?31.3‰―?32.6‰) in dust episode periods. Plant wax in the dust episode samples was mainly from herbaceous plants via long-range transport, while local plant wax was mainly from deciduous plants and woody plants. In North China coast, 83.3% of the plant wax in the severe dust episode samples was from C3 plants while 80.0% for the non-dust samples, indicating that plant wax transported to the north- western Pacific Ocean by airborne dust from East Asia was mainly from C3 plants. The results suggestthat the molecular and molecular-isotopic composi- tions of individual long-chain n-alkanes can, as an effective indicator, identify the terrestrial organic components in the dust from East Asia and sedi- ments in the northwest Pacific Ocean.展开更多
In the late 1980s the introduction of a new isotopic analytical technique of GC-C-MS that can determine the carbon isotopic composition at the molecular level has led to the appearence of the stable carbon isotopic ge...In the late 1980s the introduction of a new isotopic analytical technique of GC-C-MS that can determine the carbon isotopic composition at the molecular level has led to the appearence of the stable carbon isotopic geochemistry of biomarker compounds as a new field of scientific research. The relationship between the carbon isotopic compositions of biomarker compounds and biological precursors and diagenetic evolution is one of the key problems in this research field. Some studies on this problem have been carried out abroad in terms of organisms and modern sediments as well as the experiments of thermal simulation. Studied results show that the carbon isotopic compositions of biomarker compounds in the sediments are closely related to those in biological precursors and diagenetic evolution. For example, Reiley et al. have examined the carbon展开更多
基金This work was supported by the National Natural Science Foundation of China （Grant Nos： 40276016, 90211022）.
文摘The molecular compositions and com- pound-specific carbon isotope compositions of indi- vidual long-chain n-alkanes of atmospheric aerosols collected during two severe Asian dust episodes in Qingdao in spring of 2002 were analyzed using gas chromatography/mass spectrometry (GC/MS) and gas chromatography/isotope ratio mass spectrometry (GC/IRMS). Typical plant wax n-alkanes (C29 and C31) had lower δ 13C values than those from anthropo- genic (engine exhaust) sources (C21―C23). The av- erage δ 13C value of plant wax n-alkane C29 in non-dust episode periods was -30.5‰ (?30.3‰― ?31.9‰), while -31.3‰ (?31.1‰―?31.5‰) in dust episode periods; for C31, it was ?31.4‰ (?31.1‰― ?33.0‰) in non-dust episode periods, and ?31.7‰ (?31.3‰―?32.6‰) in dust episode periods. Plant wax in the dust episode samples was mainly from herbaceous plants via long-range transport, while local plant wax was mainly from deciduous plants and woody plants. In North China coast, 83.3% of the plant wax in the severe dust episode samples was from C3 plants while 80.0% for the non-dust samples, indicating that plant wax transported to the north- western Pacific Ocean by airborne dust from East Asia was mainly from C3 plants. The results suggestthat the molecular and molecular-isotopic composi- tions of individual long-chain n-alkanes can, as an effective indicator, identify the terrestrial organic components in the dust from East Asia and sedi- ments in the northwest Pacific Ocean.
基金Project supported by the National Natural Science Foundation of China.
文摘In the late 1980s the introduction of a new isotopic analytical technique of GC-C-MS that can determine the carbon isotopic composition at the molecular level has led to the appearence of the stable carbon isotopic geochemistry of biomarker compounds as a new field of scientific research. The relationship between the carbon isotopic compositions of biomarker compounds and biological precursors and diagenetic evolution is one of the key problems in this research field. Some studies on this problem have been carried out abroad in terms of organisms and modern sediments as well as the experiments of thermal simulation. Studied results show that the carbon isotopic compositions of biomarker compounds in the sediments are closely related to those in biological precursors and diagenetic evolution. For example, Reiley et al. have examined the carbon
