Protein function depends critically on the synergy between structure and dynamics. Due to this, describing a single native structure for protein is often insufficient to describe its function. Therefore, our group is interesting in using traveling wave ion mobility mass spectrometry (TWIM-MS) to rapidly assess the structural dynamics of biomolecules in the gas phase. It has been challenging to extract reliable data on protein flexibility from the width of IM arrival time distributions (ATDs), especially on the commercially available traveling wave devices because of the dynamic nature of the electric field. We plan to use peak width from TWIM ATDs as a means to evaluate the size of the ensemble of structures occupied by proteins, and specifically target intrinsically disordered proteins (IDPs) that play key roles in Parkinson’s and Alzheimer’s disease.