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Positive and negative ion chemical ionization mass spectrometry of trimethylsilyl derivatives of pyrrolizidine alkaloids using NH + and OH − as the reactant ions
Author(s) -
Huizing H. J.,
De Boer F.,
Hendriks H.,
Balraadjsing W.,
Bruins A. P.
Publication year - 1986
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.1200130606
Subject(s) - pyrrolizidine , chemistry , trimethylsilyl , substituent , mass spectrometry , mass spectrum , chemical ionization , ion , fragmentation (computing) , polyatomic ion , fast atom bombardment , medicinal chemistry , organic chemistry , ionization , stereochemistry , chromatography , computer science , operating system
It is shown that the combination of positive ion and negative ion chemical ionization (PINICI) in gas chromatography/mass spectrometry of trimethylsilyl (TMS) derivatives of pyrrolizidine alkaloids (PAs) offers a rapid tentative structure elucidation of such compounds in plant material. PICI with NH 3 as the reactant gas gives abundant [MH] + ions; elimination of the necic acid produces a positive ion, corresponding to the necine base, which may carry a substituent at C 7 . NICI with OH − as the reactant ion cleaves the ester bonds, which may be present at C 7 and C 9 of the necine base or at the β‐C atom of the necic acid. This is illustrated by means of the fragmentation pattern of the PICI‐ and NICI‐mass spectra of echinatine‐(TMS) 3 7‐acetyl‐lycopsamine‐(TMS) 2 , β‐acetyl‐echinatine‐(TMS) 2 , supinine‐(TMS) 2 and curassavine‐(TMS) 3 (or stereoisomers). In this way, a number of 7‐angelyl/tiglyl (e.g. symphytine), β‐angelyl/tiglyl and β‐(iso)valeryl (not reported before) derivatives of echinatine (or isomers like lycopsamine and intermedine) and of PAs with a saturated necine base, like trachelanthamine (or stereoisomers), could be shown in Symphytum taxa, Anchusa officianlis L. and Eupatorium cannabinum L.