植物生态学报 ›› 2018, Vol. 42 ›› Issue (2): 143-152.doi: 10.17521/cjpe.2017.0206

所属专题: 稳定同位素生态学

• 综述 •    下一篇

稳定同位素红外光谱技术测定CO2同位素校正方法的研究进展

庞家平1,2,温学发1,3,*()   

  1. 1 中国科学院地理科学与资源研究所生态系统网络观测与模拟重点实验室, 北京 100101
    2 中国科学院南京地理与湖泊研究所流域地理学重点实验室, 南京 210008
    3 中国科学院大学资源与环境学院, 北京 100190
  • 出版日期:2018-02-20 发布日期:2018-04-16
  • 通讯作者: 温学发 E-mail:wenxf@igsnrr.ac.cn
  • 基金资助:
    国家重点研发计划(2016YFC0500102);和国家自然科学基金(31470500)

A review of the calibration methods for measuring the carbon and oxygen isotopes in CO2 based on isotope ratio infrared spectroscopy

Jia-Ping PANG1,2,Xue-Fa WEN1,3,*()   

  1. 1 Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
    2 Key Laboratory of Watershed Geographic Sciences, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China
    3 College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100190, China
  • Online:2018-02-20 Published:2018-04-16
  • Contact: Xue-Fa WEN E-mail:wenxf@igsnrr.ac.cn
  • Supported by:
    Supported by the National Key Research and Development Project of China (2016YFC0500102)(2016YFC0500102);the National Natural Science Foundation of China(31470500)

摘要:

稳定同位素红外光谱(IRIS)技术克服了传统的大气CO2气瓶采样-同位素质谱(IRMS)技术时间分辨率低且耗时费力的缺点, 可以实现高时间分辨率和高精度的大气CO2碳同位素组成(δ 13C)和氧同位素组成(δ 18O)的原位连续测定。基于IRIS技术测量CO2 δ 13C和δ 18O的误差来源主要包括δ 13C和δ 18O测量值对CO2浓度变化的非线性响应(浓度依赖性)以及对环境条件变化的敏感性导致的漂移(时间漂移)。如何有效地校正浓度依赖性和时间漂移导致的误差是IRIS仪器应用的前提。该综述阐述了δ 13C和δ 18O测量值的浓度依赖性产生的理论基础, 回顾了浓度依赖性的理论校正和经验方程校正方法和应用; 回顾了时间漂移的校正原理、方法和应用; 概述了数据溯源至国际标准的原理、方法与应用现状。结合实际情况推荐利用3个或3个以上已知CO2浓度和δ 13C、δ 18O真值的CO2标准气体涵盖待测气体CO2浓度的浓度依赖性校正, 设置适当的校正频率校正时间漂移并进行数据溯源。指出应该加强不同仪器和校正方法的比对研究; 采用IRIS技术测定CH4、N2O和H2O同位素组成也可以采取类似的校正方法。

关键词: 稳定同位素红外光谱, 浓度依赖性, 时间漂移, 数据溯源, 校正频率

Abstract:
With the development of isotope ratio infrared spectroscopy (IRIS) technology, it is now possible for the in situ high temporal resolution and high precision measurement of carbon isotopic composition (δ 13C) and oxygen isotopic composition (δ 18O) of atmospheric CO2, which overcomes the low temporal resolution and labor intensive shortcoming of traditional isotope ratio mass spectrometry (IRMS). The dependence of δ 13C and δ 18O on CO2 concentration (termed as concentration dependence) and the drift due to sensitivity to changing environmental conditions (termed as instrumental drift) are the two main sources of error affecting the IRIS measurements. Therefore, it is important to obtain precise measurements by constructing a proper calibration strategy to solve the concentration dependence and instrumental drift. In this study, we briefly discussed the definition and related theoretical principle of concentration dependence, and elaborated the theoretical and empirical calibration methods of concentration dependence. Moreover, we introduced the calibration methods of instrumental drift, and reviewed the state of the art of calibration methods and its application of IRIS technology. Additionally, we briefly discussed the definition and method of data traceability to the international standard, and reviewed its application of IRIS technology. Finally, we recommend that concentration dependence is corrected by using three standards or above with known CO2 concentration and its δ 13C and δ 18O, bracketing the CO2 concentration of samples. The instrumental drift is corrected by setting appropriate calibration frequency and all dataset are traceable to the international standard. In the future, the comparative study of different IRIS instruments and calibration methods should be enhanced, and the similar methods should be used for measuring CH4, N2O and H2O isotopes by IRIS technique. The IRIS technology combined with other technology will provide a new opportunity for ecological research.

Key words: isotope ratio infrared spectroscopy, concentration dependence, instrumental drift, traceability to the international standard, calibration frequency