谱图相似度分析结合保留指数对单萜烯同分异构体的GC-MS定性分析

Qualitative Analysis of Monoterpene Isomers by GC-MS with Spectral Similarity Analysis and Retention Index

运用欧氏距离的最短距离聚类分析法,对在质谱数据库NIST02.L检索到的37种单萜烯同分异构体的93张质谱图进行了分类。结果显示,单萜烯被分成5类,大部分单萜烯聚到1类,包括30种单萜烯的77张质谱图。但部分谱图很近似,仅用传统的质谱库匹配鉴定其结构存在一定的困难。采用改进的谱图相似度分析结合保留指数实现了有效定性,并将该方法用于实际样品的定性分析。

93 pieces of mass spectra for 37 kinds of monoterpene isomers, collected from the NIST02. L library database, were classified by cluster analysis. The monoterpene isomers were classified into five groups, and most of them were clustered into one group which consisted of 77 pieces of the mass spectra containing 30 kinds of monoterpene isomers. Some of the mass spectra were very similar. It is difficult to identify these compounds only by the traditional mass spectrum search. A new qualitative approach was proposed for the identification of these isomers by retention index and improved spectral similarity analysis, in which the contribution to spectral similarity base peak were eliminated. The differences among the mass spectra of these isomers could be reflected more signifi- cantly. This method was applied in the qualitative analysis for the volatile components from Mentha hapioealyx Briq and flavor. Results showed that most of the monoterpene isomers could be identified easily and effectively by the proposed method.