Final Exam – Haley Schramm

About the event

Speaker: Haley Schramm

Group: Prof. Brian Clowers

Title: Quantitative Evaluation of Simultaneous Selective Ion Clustering and Hydrogen/Deuterium Exchange

Abstract: Recent efforts in ion mobility coupled to mass spectrometry have enhanced the confidence in describing gas-phase ion structures. Hydrogen/deuterium exchange is highly studied in condensed phases as a chemical tool for indirect structural analysis, but wider adoption of gas-phase methods is hindered by low deuterium incorporation and restrictions of in vacuo experiments. To combine the chemical tools of ion clustering and isotope exchange with the physical separation tool of ion mobility, an atmospheric pressure drift cell was used as a reaction vessel. The increased collision rate of ions and neutrals at ambient conditions enabled increased exchange for amino acids and peptides and comparable exchange levels in proteins in millisecond reactions times. The multimodal data obtained from this method shows a direct link between localized ion solvation and exchange kinetics. Multiple distinctly reactive ion populations are detected in all the analytes studied with unprecedented speed and selectivity. These experiments elucidated new insights into the structure and solvation of single amino acids, peptide, and protein ions currently unattainable with commercial instrumentation.