Measurement of the abundance of 14CO in the atmosphere and the 13C/12C and 18O/16O ratio of atmospheric CO with applications in New Zealand and Antarctica
Measurement of the abundance of 14CO in the atmosphere and the 13C/12C and 18O/16O ratio of atmospheric CO with applications in New Zealand and Antarctica
复制标题
测量大气中 14CO 的丰度以及大气 CO 的 13C/12C 和 18O/16O 比率并在新西兰和南极洲应用
DOI：
10.1029/93jd00587
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发表时间：
1993
影响因子：
--
通讯作者：
C. Brenninkmeijer
中科院分区：
文献类型：
--
作者：
C. Brenninkmeijer
介绍了环境空气中CO的14C、13C和18O同位素分析的设备和方法，以及南极洲和新西兰的新结果。采用了高流量的低温萃取系统，将CO氧化成CO2后分离出来，并结合了一种新型的超高效低温捕集器。可以分析数量从几百升到2立方米、CO浓度从十亿分之二十(Ppbv)到1000 ppbv的空气。CO的绝对浓度是用容量法测定的。用质谱仪测定了13C/12C和18O/16O的比值。对于180℃，对来自氧化剂的二氧化碳中的氧进行了校正。碳14的测定采用加速器质谱仪。在此之前，具有高比活度的非常小的CO衍生样品被准确稀释。对于受污染的空气，比活度随CO水平的增加而成比例地下降。新西兰和南极背景空气中~(14)CO丰度和CO浓度差异不大，具有明显的季节变化规律，尤其是~(14)CO主要受OH季节性强迫。14CO丰度在2月份的最低值约6到8月份的最高值每厘米空气约13个分子(STP)之间波动。CO具有较小的季节性，而由于当地的CO来源，表现出较大的散布。在本报告所述期间，太阳活动的变化对14CO的影响很小。14CO的大部分短期变化是由于不同气团的采样所致。由此可见，~(14)CO的变化可能反映了OH的年际变化。Scott基地的~(13)C/~(12)C和~(18)O/~(16)O都表现出较大的季节变化，并用生物质燃烧和CO分解中的同位素分馏作用来解释各自的同位素组成。
Equipment and method for accurate and precise concentration, 14C, 13C, and 18O isotope analysis for CO in background air is presented along with new results for Antarctica and New Zealand. High flow rate cryogenic extraction systems which separate CO after its oxidation to CO2 are used, incorporating a novel ultraefficient cryogenic trap. Air in quantities from a few hundred liters to 2 m3 with CO concentrations from 20 part per billion by volume (ppbv) to 1000 ppbv can be analyzed. The absolute CO concentration is determined volumetrically. The 13C/12C and 18O/16O ratios are determined by mass spectrometry. For 18O a correction is applied for the oxygen in the CO2 derived from the oxidant. Carbon 14 is determined by accelerator mass spectrometry. Prior to this the very small CO-derived samples with their high specific activity are diluted accurately. For polluted air the proportional decrease in specific activity with increasing CO levels is confirmed. The 14CO abundance and CO concentration in background air in New Zealand and Antarctica are not much different, and both follow a distinct seasonal pattern, in particular 14CO which is mainly forced by OH seasonality. The 14CO abundance swings between its February minimum of about 6 and its August maximum of about 13 molecules per cm3 air (STP). CO has a smaller seasonality and shows a larger scatter due to local CO sources. The impact of changes in solar activity on 14CO for the period considered has been small. Most of the short-term variability in 14CO is due to the sampling of different air masses. It appears that interannual OH variations may be reflected in 14CO variations. Both 13C/12C and 18O/16O at Scott Base show large seasonal variation, and the impact of biomass burning and isotopic fractionation in CO destruction are used to try to explain the respective isotopic compositions.
优化氮气流中的 [11C]CO2 捕集效率。
DOI：
10.1016/0883-2889(92)90123-v
发表时间：
1992
期刊：
International journal of radiation applications and instrumentation. Part A, Applied radiation and isotopes
影响因子：
--
作者：
Smith,RD;Mach,RH;Morton,TE;Dembowski,BS;Ehrenkaufer,RL
通讯作者：
Ehrenkaufer,RL