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High‐resolution mass spectrometry and hydrogen/deuterium exchange study of mitorubrin azaphilones and nitrogenized analogues
Author(s) -
Svilar Ljubica,
StankovJovanovic Vesna,
Lesage Denis,
Dossmann Héloïse,
Tabet JeanClaude
Publication year - 2012
Publication title -
journal of mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 1076-5174
DOI - 10.1002/jms.3044
Subject(s) - chemistry , protonation , mass spectrometry , hydrogen–deuterium exchange , fragmentation (computing) , deuterium , molecule , dissociation (chemistry) , electrospray ionization , proton affinity , triple quadrupole mass spectrometer , analytical chemistry (journal) , tandem mass spectrometry , chromatography , selected reaction monitoring , organic chemistry , ion , physics , quantum mechanics , computer science , operating system
Azaphilones represent numerous groups of wild fungal secondary metabolites that exhibit exceptional tendency to bind to nitrogen atoms in various molecules, especially those containing the amine group. Nitrogenized analogues of mitorubrin azaphilones, natural secondary metabolites of Hypoxylon fragiforme fungus, have been detected in the fungal methanol extract in very low concentrations. Positive electrospray ionization interfaced with high‐resolution mass spectrometry was applied for confirmation of the elemental composition of protonated species. Collision‐induced dissociation (CID) experiments have been performed, and fragmentation mechanisms have been proposed. Additional information regarding both secondary metabolite analogue families has been reached by application of gas‐phase proton/deuterium (H/D) exchanges performed in the collision cell of a triple quadrupole mass spectrometer. An incomplete H/D exchange with one proton less than expected was observed for both protonated mitorubrin azaphilones and their nitrogenized analogues. By means of the density functional theory, an appropriate explanation of this behavior was provided, and it revealed some information concerning gas‐phase H/D exchange mechanism and protonation sites. Copyright © 2012 John Wiley & Sons, Ltd.