Determination of the glycosidic linkage in peracetylated disaccharides comprised of D-glucopyranose units by use of desorption electron-ionization mass spectrometry.
An oxonium ion at m/z317 is present in the desorption electron ionization and ammonia desorption chemical ionization mass spectra of peracetylated disaccharides, comprised of glucopyranose units linked (1-->2), (1-->3), (1-->4) and (1-->6), but is absent in the spectra of the (1-->1)-linked isomer. The ion at m/z317, which is derived from the reducing moiety, has an O-formyl group at the position of linkage to the non-reducing moiety, and O-acetyl groups at each of the remaining positions. The isomeric monoformyl, triacetyl oxonium ions (at m/z317), derived from the (1-->2)-, (1-->3)-, (1-->4)- and (1-->6)-linked disaccharides, give distinctly different mass-analysed ion kinetic energy spectra, thereby enabling the linkage position to be assigned unambiguously.
Peltier
J M
JM
Department of Chemistry, McMaster University, Hamilton, Ontario, Canada.
MacLean
D B
DB
Szarek
W A
WA
D000107:Acetylation; D002236:Carbohydrate Conformation; D004187:Disaccharides / Q000032:analysis*; D004563:Electrochemistry; D006027:Glycosides / Q000032:analysis*; D013058:Mass Spectrometry
D004187:Disaccharides; D006027:Glycosides