Identification by GC—MS of cymene isomers and 3,7,7-trimethylcyclohepta-1,3,5-triene in essential oils
作者:E. P. Romanenko、A. V. Tkachev
DOI:10.1007/s10600-006-0256-6
日期:2006.11
Retention indices of cymene isomers published in popular GC—MS atlases were found to be erroneous by analyzing synthetic samples. The following retention indices (RI) were found using a nonpolar phase (diphenyl: dimethylpolysiloxane, 5:95) for four essential-oil components with indistinguishable mass spectra: 3,7,7-trimethylcyclohepta-1,3,5-triene (RI = 970), m-cymene (RI = 1022), p-cymene (RI = 1024), and o-cymene (RI = 1039). The relative distributions of these compounds were evaluated based on the analysis of about 1000 essential oils. Simple methods were given for preparing standard mixtures of isomeric compounds for identification by GC—MS.
通过分析合成样品,发现流行GC-MS图谱集中收录的对甲酚异构体的保留指数存在错误。使用非极性相(二苯基:二甲基硅氧烷,5:95)测定了四种无法通过质谱区分的精油成分的保留指数,分别为:3,7,7-三甲基环庚三烯(RI=970),间甲酚(RI=1022),对甲酚(RI=1024)和邻甲酚(RI=1039)。这些化合物的相对分布是根据约1000种精油的分析结果评估的。文章还提供了通过GC-MS鉴定异构化合物标准混合物的简单方法。