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. (25th August 2015)

• Record Type: Journal Article
• Authors: Banoub, Joseph H.; Demian, Wael L. L.; Piazzetta, Paolo; Sarkis, George; Kanawati, Basem; Lafont, Dominique; Laurent, Nicolas; Vaillant, Celine; Randell, Edward; Giorgi, Gianluca; Fridgen, Travis D.
• Is Part Of: Rapid communications in mass spectrometry. Volume 29:Number 19(2015)
• Page Start: 1717
• Page End: 1732
• Publication Date: 2015-08-25
• Subjects: Mass spectrometry -- Periodicals; 543.65
• DOI: 10.1002/rcm.7269
• Languages: English
• ISSNs: 0951-4198

Abstract

<abstract abstract-type="main"> <title> <x xml:space="preserve">Abstract</x> </title> <sec id="rcm7269-sec-0001" sec-type="section"> <title>Rationale</title> <p>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‐GalN<sub>3</sub> moiety. We describe the novel and unique <italic>in situ</italic> gas‐phase formation of a <italic>C</italic>‐glycoside ion formed during all these gas‐phase processes and propose a reasonable mechanism for its formation.</p> </sec> <sec id="rcm7269-sec-0002" sec-type="section"> <title>Methods</title> <p>The synthetic amphiphilic glycolipids were composed of the 2‐deoxy‐2‐azido‐D‐galactosyl moiety (GalN<sub>3</sub>, 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.</p> </sec> <sec id="rcm7269-sec-0003" sec-type="section"> <title>Results</title> <p>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]<sup>+</sup> and [M+NH<sub>4</sub>]<sup>+</sup> 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–N<sub>2</sub>]<sup>+</sup>, [cholestadiene+H]<sup>+</sup>, 2‐deoxy‐2‐D‐azido‐galactosyl [GalN<sub>3</sub>]<sup>+</sup>, [GalNH]<sup>+</sup> and [sugar−Spacer+H]<sup>+</sup> ions.</p> </sec> <sec id="rcm7269-sec-0004" sec-type="section"> <title>Conclusions</title> <p>The gas‐phase formation of the [C‐glycoside+H–N<sub>2</sub>]<sup>+</sup> 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]<sup>+</sup> ions and it was found to occur by an intramolecular rearrangement involving an ion‐molecule complex. CID‐QqTOF‐MS/MS and CID‐FTICR‐MS<sup>2</sup> analysis allowed the differentiation of the two glycolipid anomers and showed noticeable variation in the intensities of the product ions. Copyright © 2015 John Wiley & Sons, Ltd.</p> </sec> </abstract>