利用2DCOS进行多组分混合气体傅里叶变换红外光谱分析中同分异构体谱峰的辨别

在利用傅里叶变换红外光谱进行混合气体定量分析中，针对烃类尤其是同分异构体等构成的混合气体其谱图特征相似、吸收峰严重交叠，不易进行特征吸收成分的判别和特征变量选择的问题，为增强谱峰分辨力，采用广义二维相关光谱和傅里叶变化红外光谱对烃类混合气体分析中同分异构体进行辨别，以异丁烷和正丁烷的红外光谱及受浓度扰动组成的光谱组为例进行二维相关红外光谱分析。通过观察全波段和主吸收峰波段单组分气体的傅里叶变换红外光谱，可知其谱图相似，吸收峰严重交叠，如果混合在一起，将基本无法辨别何种分子结构及成分。通过广义二维相关光谱的变换，其二维相关光谱的同步谱和异步谱可以清晰地辨别出异丁烷和正丁烷的特征吸收峰及其各自强度，实验结果可知，异丁烷在2 893，2 954和2 977 cm-1，正丁烷在2 895和2 965 cm-1具有强的吸收特征谱线。分析结果初步验证了二维红外相关光谱在多组分混合气体傅里叶变换红外光谱定量分析中谱分辨率增强方面的应用。

Using 2-DCOS to Identify the Molecular Spectrum Peaks for the Isomer in the Multi-Component Mixture Gases Fourier Transform Infrared Analysis

The generalized two-dimensional correlation spectroscopy and Fourier transform infrared were used to identify hydrocarbon isomers in the mixed gases for absorption spectra resolution enhancement. The Fourier transform infrared spectrum of n-butane and iso-butane and the two-dimensional correlation infrared spectrum of concentration perturbation were used for analysis as an example. The all band and the main absorption peak wavelengths of Fourier transform infrared spectrum for single component gas showed that the spectra are similar, and if they were mixed together, absorption peaks overlap and peak is difficult to identify. The synchronous and asynchronous spectrum of two-dimensional correlation spectrum can clearly identify the iso-butane and normal butane and their respective characteristic absorption peak intensity. Iso-butane has strong absorption characteristics spectrum lines at 2 893, 2 954 and 2 893 cm-1, and n-butane at 2 895 and 2 965 cm-1. The analysis result in this paper preliminary verified that the two-dimensional infrared correlation spectroscopy can be used for resolution enhancement in Fourier transform infrared spectrum quantitative analysis.