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
Carbon isotopic compositions of individual n-alkanols and sterols in modern sediments from the Nan-sha Islands sea area are measured after derivatization to trimethylsilyl ethers by the new isotopic analytical techniq...Carbon isotopic compositions of individual n-alkanols and sterols in modern sediments from the Nan-sha Islands sea area are measured after derivatization to trimethylsilyl ethers by the new isotopic analytical technique of GC/C/IRMS. The effects of the three added silyl carbon atoms in every alcohol molecule on these compound isotopic compositions and the characteristics of their carbon isotopic compositions are studied. Then their biological sources are discussed using their carbon isotopic compositions.展开更多
为了辨别浓香型白酒(strong-flavor Baijiu,SFB)的品牌,利用稳定同位素质谱仪(stable isotope ratio mass spectrometry,IRMS)测定了来自13个品牌共计301个浓香型白酒样品的乙醇、风味物质(异戊醇、己酸乙酯、乳酸乙酯、己酸)稳定碳同...为了辨别浓香型白酒(strong-flavor Baijiu,SFB)的品牌,利用稳定同位素质谱仪(stable isotope ratio mass spectrometry,IRMS)测定了来自13个品牌共计301个浓香型白酒样品的乙醇、风味物质(异戊醇、己酸乙酯、乳酸乙酯、己酸)稳定碳同位素比值(stable carbon isotope ratios,δ^(13)C)。结果发现,不同品牌浓香型白酒拥有不同稳定碳同位素特征,单独利用乙醇δ^(13)C对浓香型白酒品牌进行判别时,总正确判别率较低,只有44.5%,结合4种风味物质δ^(13)C后,总正确判别率提升到82.7%,说明浓香型白酒中多种物质δ^(13)C相联合的方法能有效的辨别浓香型白酒的品牌。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 and Project of the Multidisciplinary Oceanographic Expedition of Chinese Academy of Sciences to Nansha Islands
文摘Carbon isotopic compositions of individual n-alkanols and sterols in modern sediments from the Nan-sha Islands sea area are measured after derivatization to trimethylsilyl ethers by the new isotopic analytical technique of GC/C/IRMS. The effects of the three added silyl carbon atoms in every alcohol molecule on these compound isotopic compositions and the characteristics of their carbon isotopic compositions are studied. Then their biological sources are discussed using their carbon isotopic compositions.
文摘为了辨别浓香型白酒(strong-flavor Baijiu,SFB)的品牌,利用稳定同位素质谱仪(stable isotope ratio mass spectrometry,IRMS)测定了来自13个品牌共计301个浓香型白酒样品的乙醇、风味物质(异戊醇、己酸乙酯、乳酸乙酯、己酸)稳定碳同位素比值(stable carbon isotope ratios,δ^(13)C)。结果发现,不同品牌浓香型白酒拥有不同稳定碳同位素特征,单独利用乙醇δ^(13)C对浓香型白酒品牌进行判别时,总正确判别率较低,只有44.5%,结合4种风味物质δ^(13)C后,总正确判别率提升到82.7%,说明浓香型白酒中多种物质δ^(13)C相联合的方法能有效的辨别浓香型白酒的品牌。
