中文摘要：

在不稳定的混合物的传统的研究，一些踪迹级的混合物不能被煤气的层析团 spectrometry 识别。目标和 targeted 以后方法与混合四极 time-of-flight 团 spectrometry 在联合基于煤气的层析在新鲜草地庄稼(Lolium perenne L.) 在踪迹级的不稳定的混合物的调查被使用。根据出版的文学，目标分析被使用保留索引，典型离子的精确群众和秒阶段团系列(MS2 系列) 执行。并且一系列实验证明低电子冲击能对许多的改进有益低丰富分子的离子山峰。提高许多分子的离子山峰是的低丰富对质的分析有益。完全， 60 不稳定的混合物被识别，哪个是 benzeneacetaldehyde (14.8%) 的大多数混合物， 2,5-dimethyl-pyrazine (9.6%) ，和 hexanal (9.3%) 。鉴定被质量应允光谱搜索，保留索引和典型离子的精确群众。

英文摘要：

In the traditional research of volatile compounds, some trace-level compounds could not be identified by gas chromatography-mass spectrometry. Target and post-targeted methods were applied in the investigation of trace-level volatile compounds in fresh turf crop （Lolium perenne L.） based on gas chromatography in combination with hybrid quadrupole time-of-flight mass spectrometry. According to literatures published, a target analysis was performed by using retention index, accurate masses of characteristic ions and second-stage mass spectra （MS2 spectra）. And a series of experiments showed that low electron impact energy was beneficial to the improvement of the abundances of low abundance molecular ion peak. peak was beneficial to qualitative analysis. Totally, 60 Enhancing the abundances of low abundance molecular ion volatile compounds were identified, the great majority cornpounds of which were benzeneacetaldehyde （14.8%）, 2,5-dimethyl-pyrazine （9.6%）, and hexanal （9.3%）. Identification was complied by mass spectral search, retention index and accurate masses of characteristic ions.