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环丙烷脂肪酸是种子油脂和细菌脂质的重要组成部分。人们曾用质谱来确定链上环丙烷的位置,然而位置异构的环丙烷酸以及简单的衍生物(如甲酯)的质谱特征极不明显,因而不能用于鉴别的目的。化学修饰是用来改善谱形并增加谱中结构信息的一种重要方法。文献报道用氢解或其它反应来使环丙烷环开裂,或借助于“远端修饰”(“remote site modifica-tion”)将环丙烷酸中的羧基改变成相应的四氢吡咯酰胺或菸醇酯再进行质谱分析,以判断环丙烷基的位置。这些方法操作不便或图谱特征不强,因而需要寻找更有效的鉴定方法。
Cyclopropane fatty acids are an important part of seed oils and bacterial lipids. Mass spectrometry has been used to determine the position of cyclopropane in the chain, whereas the positional isomeric cyclopropane acids and simple derivatives such as methyl esters have very limited mass spectral characteristics and can not be used for identification purposes. Chemical modification is an important method used to improve the shape of the spectrum and to increase the structural information in the spectrum. It has been reported in the literature that the cyclopropane ring is cleaved by hydrogenolysis or other reactions or the carboxyl group in cyclopropanoic acid is changed to the corresponding tetrahydropyrrolamide or nicotinyl alcohol by means of “remote site modification” The ester was subjected to mass spectrometry to determine the position of the cyclopropyl group. These methods are inconvenient to manipulate or have poorly characterized features and therefore need to find more effective identification methods.