Über die Strukturen von Fragmentionen im Massenspektrometer: Das Ion m/e 84 aus Lysinmethylester

The origin of the C₅H₁₀N]⁺ ion (m/e 84)—the base peak in the mass spectrum of lysine methyl ester—has been investigated. C₅H₁₀N]⁺ is generated after two successive fragmentation reactions, the first of which is the formation of C₅H₁₃N₂]⁺ (m/e 101) by loss of ·COOCH₃ from \documentclass{article}\pagestyle{empty}\begin{document}$ \left{{\rm lysine methyl ester}} \right]_{}^{_.^ + } $\end{document}, followed by loss of NH₃ in a second step. A high degree of symmetry in the diamine fragment C₅H₁₃N₂]⁺ can be concluded from the fragmentation pattern of nine differently labelled lysine methyl esters. The results can be most easily explained by postulating an ion structure in which both nitrogen atoms are in identical positions.