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为阐明维吾尔族药阿纳其根中N-烷基酰胺类成分的质谱裂解机制,采用电喷雾离子源(ESI)正离子模式进行多级碎片解析,对阿纳其根中分离得到5种N-烷基酰胺类成分:十-2E,4E-二烯酸-异丁基胺,十一-2E,4E-二烯-8,10二炔酸-苯乙胺,十-2E,4E-二烯酸-4-羟基苯乙胺,十二-2E,4E-二烯酸-4-羟基苯乙胺和十四-2E,4E-二烯酸-4-羟基苯乙胺,应用密度泛函(DFT)法比较不同裂解方式的优化结构,并分析其可能的质谱裂解机制。结果表明,在正离子模式下,5种N-烷基酰胺类成分均易形成[M+H]+准分子离子,并进一步发生N-位的α裂解,丢失酰胺结构中胺部分、羰基以及水等而形成碎片离子。该类化合物的裂解规律可为N-烷基酰胺类化合物的结构鉴定和定量分析奠定理论基础。
In order to elucidate the mechanism of mass spectroscopic cleavage of N-alkylamides in the anigena root of Uygur medicine, the electrospray ionization (ESI) positive ion mode was used to analyze the fragmentation of N-alkylamides. Five N - Alkylamides Components: Deca-2E, 4E-dienoic acid-isobutylamine, undec-2E, 4E-dien-8,10 dioleic acid-phenethylamine, 4-hydroxyphenethylamine, dodec-2E, 4E-dienoate and 4-hydroxy phenethylamine of 14E-dienoic acid, using density functional theory (DFT) method to compare the optimized structure of different pyrolysis modes and analyze the possible mechanism of mass spectrometry cleavage. The results showed that all of the five N-alkylamides could easily form [M + H] + in the positive mode, and further the α-cleavage occurred in the N-position, losing the amine moiety in the amide structure, the carbonyl group and Water and the formation of fragment ions. The cleavage regularity of these compounds can lay a theoretical foundation for the structure identification and quantitative analysis of N-alkylamides.