Freund Dana M, Sammons Katherine A, Makunga Nokwanda P, Cohen Jerry D, Hegeman Adrian D
Department of Horticultural Science, Microbial and Plant Genomics Institute, University of Minnesota;
Department of Horticultural Science, Department of Plant and Microbial Biology, Microbial and Plant Genomics Institute, University of Minnesota.
J Vis Exp. 2018 Jun 21(136):57949. doi: 10.3791/57949.
Plants produce thousands of small molecules that are diverse in their chemical properties. Mass spectrometry (MS) is a powerful technique for analyzing plant metabolites because it provides molecular weights with high sensitivity and specificity. Leaf spray MS is an ambient ionization technique where plant tissue is used for direct chemical analysis via electrospray, eliminating chromatography from the process. This approach to sampling metabolites allows for a wide range of chemical classes to be detected simultaneously from intact plant tissues, minimizing the amount of sample preparation needed. When used with a high-resolution, accurate mass MS, leaf spray MS facilitates the rapid detection of metabolites of interest. It is also possible to collect tandem mass fragmentation data with this technique to facilitate a compound identification. The combination of accurate mass measurements and fragmentation is beneficial in confirming compound identities. The leaf spray MS technique requires only minor modifications to a nanospray ionization source and is a useful tool to further expand the capabilities of a mass spectrometer. Here, fresh leaf tissue from Sceletium tortuosum (Aizoaceae), a traditional medicinal plant from South Africa, is analyzed; numerous mesembrine alkaloids are detected with leaf spray MS.
植物会产生数千种化学性质各异的小分子。质谱分析（MS）是分析植物代谢物的一项强大技术，因为它能以高灵敏度和特异性提供分子量信息。叶片喷雾质谱分析是一种常压电离技术，通过电喷雾将植物组织用于直接化学分析，省去了色谱分析步骤。这种代谢物采样方法能够同时从完整植物组织中检测多种化学类别，将所需的样品制备量减至最少。当与高分辨率、精确质量的质谱仪联用时，叶片喷雾质谱分析有助于快速检测目标代谢物。使用该技术还能够收集串联质谱碎片数据以辅助化合物鉴定。精确质量测量和碎片分析相结合有助于确认化合物的身份。叶片喷雾质谱技术只需对纳米喷雾电离源做少许改进，是进一步拓展质谱仪功能的有用工具。在此，对来自南非传统药用植物南非睡茄（番杏科）的新鲜叶片组织进行了分析；通过叶片喷雾质谱分析检测到了多种美索勃莫宁生物碱。
