Open Access Green as soon as Postprint is submitted to ZB.
The in situ gas-phase formation of a C-glycoside ion obtained during electrospray ionization tandem mass spectrometry. A unique intramolecular mechanism involving an ion-molecule reaction.
Rapid Commun. Mass Spectrom. 29, 1717-1732 (2015)
RATIONALE: This study examines the electrospray ionization mass spectrometry (ESI-MS), in-source collision-induced dissociation (CID) fragmentation and low-energy collision-induced dissociation tandem mass spectrometry (CID-MS/MS) of a synthetic pair of β- and α-anomers of the amphiphilic cholesteryl polyethoxy neoglycolipids containing the 2-azido-2-deoxy-D-galactosyl-D-GalN3 moiety. We describe the novel and unique in situ gas-phase formation of a C-glycoside ion formed during all these gas-phase processes and propose a reasonable mechanism for its formation. METHODS: The synthetic amphiphilic glycolipids were composed of the 2-deoxy-2-azido-D-galactosyl moiety (GalN3 , the hydrophilic part) covalently attached to a polyethoxy spacer which is covalently linked to the cholesteryl moiety (hydrophobic part). The 2-azido-2-deoxy-α- and β-D-galactosyl-containing glycolipids were studied by in-time and in-space ESI-MS and CID-MS/MS in positive ion mode, with quadrupole ion trap (QIT), quadrupole-quadrupole-time-of-flight (QqTOF), and Fourier transform ion cyclotron resonance (FTICR) instruments. RESULTS: Conventional single-stage ESI-MS analysis showed the formation of the protonated molecule. During the single-stage ESI-MS analysis and the CID-MS/MS of the [M+H](+) and [M+NH4 ](+) adducts obtained from both glycolipid anomers, the presence of a series of specific product ions with different intensities was observed, consistent with the [C-glycoside+H-N2 ](+) , [cholestadiene+H](+) , 2-deoxy-2-D-azido-galactosyl [GalN3 ](+) , [GalNH](+) and [sugar-Spacer+H](+) ions. CONCLUSIONS: The gas-phase formation of the [C-glycoside+H-N2 ](+) ion isolated from the glycolipid anomers was observed during both the ESI-MS of the glycolipids and the CID-MS/MS analyses of the [M+H](+) ions and it was found to occur by an intramolecular rearrangement involving an ion-molecule complex. CID-QqTOF-MS/MS and CID-FTICR-MS(2) analysis allowed the differentiation of the two glycolipid anomers and showed noticeable variation in the intensities of the product ions.
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Publication type
Article: Journal article
Document type
Scientific Article
ISSN (print) / ISBN
0951-4198
e-ISSN
1097-0231
Quellenangaben
Volume: 29,
Issue: 19,
Pages: 1717-1732
Publisher
Wiley
Non-patent literature
Publications
Reviewing status
Peer reviewed
Institute(s)
Research Unit Analytical BioGeoChemistry (BGC)