Premium
Re‐investigation of the fragmentation of protonated carotenoids by electrospray ionization and nanospray tandem mass spectrometry
Author(s) -
Neto Fausto Carnevale,
Guaratini Thais,
CostaLotufo Letícia,
Colepicolo Pio,
Gates Paul J.,
Lopes Norberto Peporine
Publication year - 2016
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.7589
Subject(s) - chemistry , tandem mass spectrometry , polyene , mass spectrometry , fragmentation (computing) , electrospray ionization , photochemistry , protonation , chromatography , ion , organic chemistry , computer science , operating system
Rationale Carotenoids are polyene isoprenoids with an important role in photosynthesis and photoprotection. Their characterization in biological matrices is a crucial subject for biochemical research. In this work we report the full fragmentation of 16 polyenes (carotenes and xanthophylls) by electrospray ionization tandem mass spectrometry (ESI‐CID‐MS/MS) and nanospray tandem mass spectrometry (nanoESI‐CID‐MS/MS). Methods Analyses were carried out on a quadrupole time‐of‐flight (QTOF) mass spectrometer coupled with a nanoESI source and on a Fourier transform ion cyclotron resonance (FTICR) mass spectrometer with an ESI source. The formulae of the product ions were determined by accurate‐mass measurements. Results It is demonstrated that the fragmentation routes observed for the protonated carotenoids derive essentially from charge‐remote fragmentations and pericyclic rearrangements, such as electrocyclic and retro‐ene eliminations (assisted or not by a sigmatropic hydrogen shift). All mechanisms are dependent on cis‐trans isomerization through the formation of several conjugated polyene carbocation intermediates. Some specific ions for the carotenoid epoxides were justified through formation of cyclic oxonium ions. Conclusions Complete fragmentation pathways of protonated carotenoids by ESI‐ and nanoESI‐CID‐MS/MS provided structural information about functional groups, polyene chain and double bonds, and contribute to identification of carotenoids based on MS/MS fragmentation patterns. Copyright © 2016 John Wiley & Sons, Ltd.