Joseph Meeuwsen, PhD - Product Marketing Manager - Agilent Technologies

Collision induced unfolding (CIU) combined with ion mobility-mass spectrometry (IM-MS) provides valuable information about biomolecule structure. Combining CIU-IM-MS with a gentle top-down fragmentation technique like electron capture dissociation (ECD) can provide additional information. For example, ECD can be used to probe different gas-phase protein structures created via CIU, and combining CIU with ECD can improve the sequence coverage of structures otherwise recalcitrant to ECD. However, it has historically been difficult to perform electron-based fragmentation in an ion trapping device after IM separation because reaction times of tens of milliseconds are required to achieve practical efficiencies. The “fly-through” design of the ExD cell with microsecond-scale transit times makes it uniquely suited to combining with millisecond-scale IM separation. Here we leverage a new ExD cell design with increased efficiency and simplified operation to probe gas-phase protein folding structures and confirm amino acid sequence.