Re-investigation of the fragmentation of protonated carotenoids by electrospray ionization and nanospray tandem mass spectrometry

Author(s)

Carnevale Neto, Fausto ; Guaratini, Thais ; Costa-Lotufo, Leticia ; Colepicolo, Pio ; Gates, Paul J. ; Lopes, Norberto Peporine

• Document type: Journal article
• Source: RAPID COMMUNICATIONS IN MASS SPECTROMETRY; v. 30, n. 13, p. 9-pg., 2016-07-15.

Abstract

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 (C) 2016 John Wiley & Sons, Ltd. (AU)

• FAPESP's process: 14/50265-3 - Distribution and metabolism of natural and synthetic xenobiotics: from the comprehension of reactional process to tissue imaging generation
• Grantee: Norberto Peporine Lopes
• Support Opportunities: BIOTA-FAPESP Program - Thematic Grants
• FAPESP's process: 14/12343-2 - Method development and prospection studies of marine biological resources with citotoxic potential based on systems biology
• Grantee: Fausto Carnevale Neto
• Support Opportunities: Scholarships in Brazil - Post-Doctoral