Ion traps provide well-defined environments for carrying out ion-neutral molecular reactions. Cryogenic temperatures in such traps allow for the formation of delicate complexes held together by non-covalent interactions. Here we present a novel dual cryogenic ion trap spectrometer capable of facilitating ion-neutral reactions as well as forming weakly-bound clusters. In our setup, reactions and clustering are done in a temperature controlled (77-300 K) trap. The second trap is used to further cool reacted species to 10 K, which can then be characterized via infrared vibrational predissociation spectroscopy.<br/><br/>Our experiments show that at 80 K, we can generate solvent clusters of more than 50 water molecules around a singly charged ion in our first trap, allowing us to probe structural changes of ions as a function of stepwise solvation. First, results showing the microsolvation of the model protonated glycylglycine peptide will be presented to demonstrate this instrumental technique. Second, I will provide data that show that H/D exchange between an all H-triglycine peptide and D2O cluster can be prevented in our trap at 80 K. This clustering scheme isolates the vibrational features of the peptide from the solvent and simplifies spectral congestion, opening the possibility to study larger and more complicated biomolecules.

Dual cryogenic ion trap spectroscopy for the formation and characterization of solvated peptides

255th National Meeting (2018)

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