• 关键词：气体稳定同位素比质谱  本底大气  CO₂  δ¹³C  δ¹⁸O

• 基金项目：国家自然科学基金青年科学基金(No.40905066);国家重点基础研究发展计划(No. 2010CB950601); 中国气象科学研究院基本科研业务费专项资金(No.2009Y003); 公益性行业科研专项(No.GYHY200806026)

• 刘立新
• 中国气象科学研究院,北京 100081

• 周凌晞
• 中国气象科学研究院,北京 100081

• 夏玲君
• 中国气象科学研究院,北京 100081

• 张芳
• 中国气象科学研究院,北京 100081

• 顾帅
• 中国气象科学研究院,北京 100081

• 摘要：将商用MAT253稳定同位素比质谱仪、Airtrap高效预浓缩气体捕集阱与自加工16口自动进样器集成,建立了高精度气体稳定同位素比质谱分析系统,用于程序化自动分析本底大气CO₂的δ¹³C和δ¹⁸O.气样分析时用工作标气定量并穿插目标气测定,还定期用实验室上一级标气对工作标气和参比气进行标校,以保证分析结果的可靠和可比.结果表明,利用不同稳定同位素比范围的标气重复进样测试,发现该系统对δ¹³C和δ¹⁸O的分析精度分别优于0.03‰和0.06‰,能基本满足本底大气CO₂的碳氧稳定同位素比分析需求和WMO/GAW质量目标.

• Abstract：A high precision gas stable isotopic ratio mass spectrometry system was set up to measure CO₂ stable isotopes in background air samples. The system consisted of a MAT253 isotopic ratio mass spectrometry, an efficient airtrap extraction line and a custom designed auto sampler. In combination with periodic target injection, two working standards were injected before and after each of the unknown sample to control and monitor the system performance. The working standards were calibrated regularly to trace back higher level reference and to ensure measurement comparability. From repeated test, the system precision was better than 0.03‰ and 0.06‰ for δ¹³C and δ¹⁸O, respectively. The system could apply to the δ¹³C and δ¹⁸O analysis in background atmospheric CO₂ and essentially meet the WMO/GAW quality target.

• Key words：gas stable isotopic ratio mass spectrometry  background atmosphere  CO₂  δ¹³C  δ¹⁸O

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