Gas phase reactivity of isomeric arylglycosides towards amines. A chemical ionization mass spectrometry and tandem mass spectrometry study.

Chemical ionization mass spectrometry (MS) and tandem mass spectrometry (MS/MS) experiments have been performed for the structural characterization and isomeric differentiation of two series of C- and O-linked arylglycosides with potential antioxidant activity. Different amines have been used for producing gas phase chemical ionization. Depending on their proton affinity and steric hindrance, adduct ions with different stability are formed. The most stable adducts are produced by ethylamine and they have been extensively structurally characterized by experimental and theoretical approaches. Energy resolved chemical ionization tandem mass spectrometric experiments have allowed unambiguous characterization and differentiation of both the anomers differing at the configuration of the glycosidic C(1) atom, and regio- and structural isomers at extremely low concentrations, typical of mass spectrometry. This study has shown that amine chemical ionization mass spectrometry and MS/MS are powerful and versatile tools for the structural characterization of arylglycosides.