Compound-specific carbon isotope compositions of individual long-chain n-alkanes in severe Asian dust episodes in the North China coast in 2002

查看全文 作　　者：GUO [1]Zhigang;LI [2]Juyuan;FENG [3]Jialiang;FANG [3]Ming;YANG [1]Zuosheng 机构地区：[1]College of Marine Geosciences, Ocean University of China, Qingdao 266003, China;[2]Institute of Geology, Shengli Oil-field Company, Petrochemical Corporation of China, Dongying 257015, China;[3]Institute for Environment and Sustainable Development, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon,Hong Kong, China 出　　处：《Chinese Science Bulletin》索引2006年第51卷第17期,共8页 基　　金：This work was supported by the National Natural Science Foundation of China (Grant Nos: 40276016, 90211022). 摘　　要：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. 关 键 词：亚洲尘暴 华北地区 碳同位素 GC-MS GC-IRMS