本文建立了采用元素分析-同位素质谱法(Element analysis-Isotope ratio mass spectrometer,EA-IRMS)测定黄芪中碳、氮稳定同位素比值的方法。该方法的稳定性和准确性均达到同位素比值测定的要求。利用该方法测定来自山西大同、陕西子...本文建立了采用元素分析-同位素质谱法(Element analysis-Isotope ratio mass spectrometer,EA-IRMS)测定黄芪中碳、氮稳定同位素比值的方法。该方法的稳定性和准确性均达到同位素比值测定的要求。利用该方法测定来自山西大同、陕西子洲、甘肃陇西和内蒙的黄芪样品的δ^(13) C、δ^(15) N值。结果表明,甘肃陇西黄芪与其它3个产地的δ^(13) C值均存在显著性差异(p<0.002),各产地黄芪的δ^(15) N值无显著性差异。利用稳定碳同位素比值,甘肃陇西黄芪能够明显地区分与其它产地,说明稳定碳同位素可应用于黄芪的产地溯源。展开更多
High-precision 210Pb dating technology was applied to a peat core with a time span of about 150 years that was taken from Hongyuan, Sichuan Province, China. The concentrations of total mercury (Hg) and stable isotope ...High-precision 210Pb dating technology was applied to a peat core with a time span of about 150 years that was taken from Hongyuan, Sichuan Province, China. The concentrations of total mercury (Hg) and stable isotope compositions of mercury in the peat core were measured using a LUMEX 915 instrument and multi-collector inductively coupled plasma mass spectrometer, respectively. Total mercury (Hg) concentrations in the peat core had a clearly increasing trend from the bottom to top of the core while δ 202Hg values (relative to NIST 3133) of peat had a decreasing trend. The total mercury (Hg) concentration varied from 16.7 to 101.3 ng/g and the δ 202Hg values ranged from –0.44‰± 0.14‰ to –1.45‰± 0.22‰. We clearly show that the study area experienced mercury pollution after the industrial revolution, and the mercury emitted from natural sources and anthropogenic sources had different Hg isotope signatures.展开更多
Branched glycerol dialkyl glycerol tetraethers (GDGTs) were analyzed in peat samples taken from the Zoigê grassland, located on the eastern margin of the Qinghai-Tibetan Plateau. The mean annual air temperature (...Branched glycerol dialkyl glycerol tetraethers (GDGTs) were analyzed in peat samples taken from the Zoigê grassland, located on the eastern margin of the Qinghai-Tibetan Plateau. The mean annual air temperature (MAAT) and pH in the 210 Pb-dating peat core were reconstructed based on the cyclization of branched tetraethers (CBT) and methylation of branched tetraethers (MBT) indices for the last 150 years. The results showed that the MAAT and pH values involved three stages of variation over the last 150 years. The pH was stable and the MAAT decreased slowly by about 1°C from 1851 to 1927. The pH decreased rapidly by 0.6 and the MAAT decreased significantly by 2.5°C between 1927 and 1979. The pH and MAAT increased by 0.8 and 5°C, respectively, since the 1980s. The reconstructed temperatures correspond well to the mean winter temperatures reconstructed using tree-rings from the Jiuzhaigou Valley, situated at the boundary between the Qinghai-Tibetan Plateau and the Sichuan Basin. The estimated MAAT was similar to the temperatures reconstructed using tree-rings, indicating an increasing trend, as shown by local instrumental records from 1957 to 2001. These results provide further confidence in the application of proxies based on glycerol dialkyl glycerol tetraethers in peat records for continental paleoclimate reconstruction.展开更多
文摘本文建立了采用元素分析-同位素质谱法(Element analysis-Isotope ratio mass spectrometer,EA-IRMS)测定黄芪中碳、氮稳定同位素比值的方法。该方法的稳定性和准确性均达到同位素比值测定的要求。利用该方法测定来自山西大同、陕西子洲、甘肃陇西和内蒙的黄芪样品的δ^(13) C、δ^(15) N值。结果表明,甘肃陇西黄芪与其它3个产地的δ^(13) C值均存在显著性差异(p<0.002),各产地黄芪的δ^(15) N值无显著性差异。利用稳定碳同位素比值,甘肃陇西黄芪能够明显地区分与其它产地,说明稳定碳同位素可应用于黄芪的产地溯源。
基金supported by the National Natural Science Foundation of China (40825011 and 20828008)
文摘High-precision 210Pb dating technology was applied to a peat core with a time span of about 150 years that was taken from Hongyuan, Sichuan Province, China. The concentrations of total mercury (Hg) and stable isotope compositions of mercury in the peat core were measured using a LUMEX 915 instrument and multi-collector inductively coupled plasma mass spectrometer, respectively. Total mercury (Hg) concentrations in the peat core had a clearly increasing trend from the bottom to top of the core while δ 202Hg values (relative to NIST 3133) of peat had a decreasing trend. The total mercury (Hg) concentration varied from 16.7 to 101.3 ng/g and the δ 202Hg values ranged from –0.44‰± 0.14‰ to –1.45‰± 0.22‰. We clearly show that the study area experienced mercury pollution after the industrial revolution, and the mercury emitted from natural sources and anthropogenic sources had different Hg isotope signatures.
基金supported by the Knowledge Innovation Program of the Chinese Academy of Sciences (KZCXZ-YW-JC103)the Foundation for Outstanding Scholarship of Guangzhou Institute of Geochemistry, Chinese Academy of Sciences (GIGRC-09-02)
文摘Branched glycerol dialkyl glycerol tetraethers (GDGTs) were analyzed in peat samples taken from the Zoigê grassland, located on the eastern margin of the Qinghai-Tibetan Plateau. The mean annual air temperature (MAAT) and pH in the 210 Pb-dating peat core were reconstructed based on the cyclization of branched tetraethers (CBT) and methylation of branched tetraethers (MBT) indices for the last 150 years. The results showed that the MAAT and pH values involved three stages of variation over the last 150 years. The pH was stable and the MAAT decreased slowly by about 1°C from 1851 to 1927. The pH decreased rapidly by 0.6 and the MAAT decreased significantly by 2.5°C between 1927 and 1979. The pH and MAAT increased by 0.8 and 5°C, respectively, since the 1980s. The reconstructed temperatures correspond well to the mean winter temperatures reconstructed using tree-rings from the Jiuzhaigou Valley, situated at the boundary between the Qinghai-Tibetan Plateau and the Sichuan Basin. The estimated MAAT was similar to the temperatures reconstructed using tree-rings, indicating an increasing trend, as shown by local instrumental records from 1957 to 2001. These results provide further confidence in the application of proxies based on glycerol dialkyl glycerol tetraethers in peat records for continental paleoclimate reconstruction.
