使用全二维气相色谱-飞行时间质谱仪分析茶叶挥发性香味成份探究

Analysis of Volatile Aroma Components of Tea by Full Two-dimensional Gas Chromatography-time of Flight Mass Spectrometer

采用全二维气相色谱-飞行时间质谱联用技术(GC×GC-TOFMS)搭载固相微萃取(SPME),通过将龙井茶叶加热,使其香气散发吸附在SPME针头的固定相上,通过GC进样口的高温解吸后进入GC×GC-TOFMS中分析,得到龙井茶的香气成分的全二维谱图;结合质谱数据库匹配、化合物保留时间、结构谱图及峰面积等对通过GC×GC-TOFMS分离得到的香气成分进行定性及相对定量分析;实验结果共分析出289个物质,分为28类物质,其中数量占比前5的是:醇类17.652%,酮类15.916%,烯烃11.418%,醛类10.726%,酯类9.342%;百分含量前5的是:烯烃38.396%,环烷烃14.557%,醇类11.497%,醛类8.887%,酮类6.168%。另外也分析出呋喃、吡嗪等常见于绿茶中的物质。通过该结果可知,GC×GC-TOFMS有强大的分离和定性功能,是GC-MS分离的组分数目的 3倍甚至更多,适用于分析茶叶中复杂的香气成分。另外,GC×GC-TOFMS分析的结果符合龙井茶及茶相关知识的文献资料的结果逻辑,与龙井茶叶的香气基本吻合。

Using full two-dimensional gas chromatography time of flight mass spectrometry(GC×GC-TOFMS) to analyze the aroma components of Longjing tea;Combined with mass spectrometry database matching, compound retention time, structural spectrum and peak area, GC×Qualitative and relative quantitative analysis of aroma components separated by GC-TOFMS;A total of 289 substances were analyzed, which were divided into 28 categories, of which the top 5 were alcohols 17.652 %, ketones 15.916 %, olefins 11.418 %, aldehydes 10.726 %, esters 9.342 %;The top 5 percentages are: olefins 38.396 %, cycloalkanes 14.557 %,alcohols 11.497 %, aldehydes 8.887 %, ketones 6.168 %. In addition, furan, pyrazine and other substances commonly found in green tea were also analyzed.According to this result, GC × GC-TOFMS has powerful separation and qualitative functions, which is 3 times or more than the fraction separated by GC-MS. it is suitable for the analysis of complex aroma components in tea. In addition, The result of GC × GC-TOFMS analysis is consistent with the logic of Longjing tea and the literature of tea related knowledge, and is basically consistent with the aroma of Longjing tea.