Stereochemical differentiation of mannose, glucose, galactose, and talose using zinc(II) diethylenetriamine and ESI-ion trap mass spectrometry.

Diastereomeric diethylenetriamine N-glycoside zinc(II) complexes are investigated using electrospray ionization followed by tandem mass spectrometry in a quadrupole ion trap. Dissociation ions specific to stereochemical differences at C2 and C4 in hexose complexes are observed in the MS2 and MS3 spectra, thus allowing unambiguous differentiation of glucose, galactose, mannose, and talose. Labeling studies incorporating 2H and 13C are used to probe the mechanisms of dissociation involved with these diastereomers, and MS2 studies on deoxyglucose complexes are implemented to support proposed sites of deprotonation within the complexes.