Coupling ion mobility with spectroscopy to characterize complex molecular ions

Elucidating on the structural and conformational complexity of biomolecules is one of the most important contemporary challenges for understanding intra- and intermolecular dynamics and kinetics of complex molecular systems. Over the last decades, gas phase chemists have directed efforts toward developing isomer-specific spectroscopies, such as multi-resonance spectroscopic schemes, that allow for a conformer- or isomer-selective structural characterization from complex molecular samples. One such development has involved coupling of ion mobility spectrometry (IMS) with action spectroscopy, allowing for an unambiguous structural deconvolution of isomerically congested samples.

This presentation will discuss the different types of IMS separation techniques that are currently used in gas phase research in combination with ion spectroscopy, focusing on the research in the Bieske (Uni Melbourne) and Rizzo (EPFL) research groups. First, I will discuss two tandem drift tube IMS instruments developed at Melbourne for the characterization of structural and photoisomerization patterns of molecular ions. I will then present an instrument recently developed at the EPFL, which couples cyclic ion mobility spectrometry using Structures for Lossless Ion Manipulation (SLIM) with high-resolution cryogenic messenger-tagging IR spectroscopy, providing vibrational spectra of mass selected biomolecular ions with ultra-high mobility resolution.