Characterization of Protonated Model Disaccharides from Tandem Mass Spectrometry and Chemical Dynamics Simulations.

The fragmentation mechanisms of prototypical disaccharides have been studied herein by coupling tandem mass spectrometry (MS) with collisional chemical dynamics simulations. These calculations were performed by explicitly considering the collisions between the protonated sugar and the neutral target gas, which led to an ensemble of trajectories for each system, from which it was possible to obtain reaction products and mechanisms without pre-imposing them. The β-aminoethyl and aminopropyl derivatives of cellobiose, maltose, and gentiobiose were studied to observe differences in both the stereochemistry and the location of the glycosidic linkage. Chemical dynamics simulations of MS/MS and MS/MS/MS were used to suggest some primary and secondary fragmentation mechanisms for some experimentally observed product ions. These simulations provided some new insights into the fundamentals of the unimolecular dissociation of protonated sugars under collisional induced dissociation conditions.