科研之友
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摘要
Nitrous oxide (N2O), an increasingly abundant greenhouse gas in the atmosphere, is the most important stratospheric ozone-depleting gas of this century. Natural abundance ratios of isotopocules of N2O, NNO molecules substituted with stable isotopes of nitrogen and oxygen, are a promising index of various sources or production pathways of N2O and of its sink or decomposition pathways. Several automated methods have been reported to improve the analytical precision for the isotopocule ratio of atmospheric N2O and to reduce the labor necessary for complicated sample preparation procedures related to mass spectrometric analysis. However, no method accommodates flask samples with limited volume or pressure. Here we present an automated preconcentration system which offers flexibility with respect to the available gas volume, pressure, and N2O concentration. The shortest processing time for a single analysis of typical atmospheric sample is 40 min. Precision values of isotopocule ratio analysis are <0.1 parts per thousand for delta N-15(bulk) (average abundances of (NNO)-N-14-N-15-O-16 and (NNO)-N-15-N-14-O-16 relative to (NNO)-N-14-N-14-O-16), <0.2 parts per thousand for delta O-18 (relative abundance of (NNO)-N-14-N-14-O-18), and <0.5 parts per thousand for site preference (SP; difference between relative abundance of (NNO)-N-14-N-15-O-16 and (NNO)-N-15-N-14-O-16). This precision is comparable to that of other automated systems, but better than that of our previously reported manual measurement system.
- 出版日期2016
