Collaborative Research: Tunable HDX and Ion-Molecule Interactions Using Doped-Gas Ion Mobility-Mass Spectrometry

With support from the Chemical Measurement and Imaging Program in the Division of Chemistry, the research groups of Professor Brian H. Clowers (Washington State University) and Professor Christopher J. Hogan (University of Minnesota) are working to improve the performance and capabilities of ion mobility spectrometry (IMS), a chemical analysis method with applications ranging from rapid screening for explosives in airports to detailed insight into the structure and function of biomolecules associated with healthy and diseased organisms. The team is devising means of using selective interactions with solvent molecules and other gaseous additives within the IMS instrument in order to enhance the ability to separate and identify molecules in complex mixtures. By combining these methods with mass spectrometry (a powerful complementary technique) and new computational tools, the research aims to provide an innovative workflow that is broadly applicable to chemical analysis. Students engaged in this research obtain unique interdisciplinary training enhanced by opportunities to work 'out-of-discipline' as part of their studies. Research opportunities are also made available to undergraduate and high school students.

Recently, Professors Clowers and Hogan have demonstrated enhanced separation factors through selective interactions between gas-phase ions and organic vapor modifiers introduced into ion mobility systems. They now seek to gain a more detailed understanding of the underlying interactions of ion-vapor complexes in order to predict and enable expanded use of IM-MS and tandem IM experiments. Their approach uses an innovative, multidimensional ion mobility/hydrogen-deuterium exchange mass spectrometry strategy and first-principles modeling of gas-phase ion-neutral interactions and vapor uptake. Primary aims are to determine (1) if thermodynamics of vapor association depend upon chemical functionality in amino acids and simple peptide ions; (2) if the extent of binding can be extrapolated as a characterization tool for larger, multiply charged ions exhibiting known secondary structure; (3) if clustering dynamics quantitatively describe the behavior of ions in high-field and asymmetric waveform experiments; and (4) if molecular dynamics can accurately describe solvated ion transport.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.