基于傅里叶变换红外光谱法CO2气体碳同位素比检测研究

摘要

介绍了基于傅里叶变换红外技术检测CO2气体碳同位素比的新方法，详细介绍了如何从HITRAN红外数据库中提取气体标准吸收截面；介绍了基于非线性最小二乘法反演CO2气体碳同位素比和整套实验装置的组成及实验步骤.从理论和实验分析两方面讨论了温度和气压变化对δ13CO2值的影响规律.对于同一CO2标准气体，采用FTIR和同位素质谱法两种技术进行了δ13CO2值对比检测，两种测量技术的平均值差异仅为0.25%.从实验结果可以看出， FTIR技术可以实现对CO2气体碳同位素比的检测.%A new method to detect carbon isotope ratio of carbon dioxide is presented, which is developed based on Fourier transform infrared spectroscopy (FTIR)technique. The method to obtain the absorption coefficient from HITRAN is introduced in detail. The nonlinear least square algorithm to determineδ13CO2 value is studied. The total system and experimental procedure are shown in the paper. The temperature and pressure effect onδ13CO2 value determination are analyzed from both theory and experiment analysis. For the same CO2 standard gas, theδ13CO2 value is detected by both FTIR and IRMS technology, and the results are also comparatively analyzed and discussed. The difference in mean between both methods is only 0.25%. The experimental results show that the FTIR technique to detect carbon isotope ratio of carbon dioxide is viable.