Multi-Approach Strategy for Probing the Unimolecular Reactivity of Gaseous Ions: Application to Sugars and Nucleotides

Conférence invitéeInternational audienceDuring the last decades, tandem mass spectrometry (MS/MS) has become an invaluable tool for probing the structure of biomolecules in the gas phase. In this context, the most widely applied strategy is to perform low-energy CID experiments on gaseous ions generated by electrospray (ESI). Although particularly useful, tandem mass spectrometry provides only little information about the spatial arrangement of ions in the gas phase, and therefore does not allow their complete structural characterization. Furthermore, there are many details of gas-phase dissociation mechanisms associated with CID which are still unclear.In order to gain more insights about the structure and unimolecular reactivity of ESI-generated biomolecular ions, we couple different experimental approaches and more particularly action spectroscopy (IR or UV) and/or ion mobility.[1] Coupled with mass spectrometry, these approaches offer value-added data that cannot be obtained by mass spectrometry alone. In parallel to experiments, we also perform QM+MM chemical dynamics simulations to model collision induced dissociation experiments. [2] With this approach, the explicit collision between the ion and the inert gas is considered and the evolution of the ion is followed. The goal of these simulations is to determine theoretical MS/MS spectra and to obtain new information about the fragmentation mechanisms involved (reaction pathways, energy transfer, dynamics,…). These different approaches will be illustrated by several examples