Gas-Phase Reactivity of Glycosides and Methyl Glycosides with Cu⁺, Ag⁺ and Pb²⁺ Ions by Fast-Atom Bombardment and Tandem Mass Spectrometry

Abstract

The analytical potential of the complexation of three isomeric monosaccharides (D-glucose, D-galactose, D-fructose)and two methyl glycosides ( O-methyl-α-D-glucose and O-methyl-β-D-glucose)by three metal ions, Ag+, Cu+ and Pb2+, has been investigated by fast-atom bombardment (FAB)ionization and tandem mass spectrometry. Our results have shown that the unimolecular reactivity of Ag+ complexes allows the characterization of the C(4)stereochemistry of the pyranose ring, whereas a distinction between D-glucose and D-fructose is not achieved. On the other hand, each of the three [Cu + monosaccharide]+ complexes exhibits specific dissociation patterns. We have also observed that Pb2+ ions induce the richest reactivity and are of particular interest for the identification of the three isomers. Finally, this study has demonstrated that the stereochemistry of the anomeric center of O-methyl-D-glucose is easily determined by reaction with Ag+ or Pb2+ ions. Several mechanisms are proposed to account for the main fragmentations of cationized glucose.

Direct analysis of Stevia leaves for diterpene glycosides by desorption electrospray ionization mass spectrometry

“…[5][6][7] Due to the sensitivity and specificity of the technique, mass spectrometry plays an important role in the detection, differentiation and structural elucidation of the natural products, with tandem mass spectrometry representing an important component of the complex mixture analysis experiment. [8][9][10][11][12] While these methods have proven successful in the analysis of the plant material, they can be laborious. Therefore, there is an interest in rapid screening methods for plant materials that require no sample preparation and yet provide specific information regarding the chemical make-up of the material.…”

Tandem mass spectra of ammonium adducts of monosaccharides: differentiation of diastereomers

“…However, it is a difficult proposition because the difference in free energy of formation of various hexoses is small (1.2 kcal mol −1 ) 20. There are several reports of achieving this through MS/MS of metal cationized mono‐ and oligosaccharides 21–30. Structural discrimination of a series of underivatized monosaccharides has been achieved through the energy resolved, collision‐induced fragmentation patterns of their non‐covalent complexes with hydrazine 31.…”

Multiple lithium exchange under lithium cationization of cyclodextrins

“…The reactivity between carbohydrates and metal ions has been widely studied in solution 3, 4. Metal ions are also commonly used in the mass spectral analysis of sugars 5, 6. Several papers have reported gas‐phase mass spectrometric studies of the complexation of carbohydrates by alkali, alkaline earth and transition metal ions.…”