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Collisional activation spectra of bisbenzylisoquinoline alkaloids
Author(s) -
Madhusudanan K. P.,
Das P. R.,
Pramanik B. N.,
Jain Sudha,
Bhakuni D. S.
Publication year - 1989
Publication title -
biomedical and environmental mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 0887-6134
DOI - 10.1002/bms.1200180916
Subject(s) - chemistry , ion , protonation , fragmentation (computing) , isoquinoline , mass spectrum , polyatomic ion , electron ionization , spectral line , stereochemistry , fast atom bombardment , ionization , crystallography , organic chemistry , physics , astronomy , computer science , operating system
Collisional activation (CA) spectra of the molecular protonated ions generated under fast atom bombardment (FAB) and the molecular ions under electron ionization (EI) from 14 bisbenzylisoquinoline alkaloids have been compared. The FAB CA spectra show mainly elimination of MeOH from the MH + ion and no characteristic fragmentation pattern. The EI spectra, on the other hand, show abundant structurally diagnostic ions free of doubly charged ions. The double benzylic cleavage results in bisisoquinoline ions giving rise to the most intense peak in the spectra of all the compounds. Loss of one of the isoquinoline moieties comprising rings C and D and elimination of both the benzyl groups (rings E and F) are characteristic of compounds containing no 1,4‐dioxine bridge (1–5). These compounds are also characterized by more abundant (>50%) [M – Me] + ions, while the compounds with a 1,4‐dioxine bridge give [M – Me] + ions with <50% abundance.