Determining Collisional Cross Sections from Ion Decay with Individual Ion Mass Spectrometry
Nickolas P. Fisher, John P. McGee, K. P. Bowen, Michael Goodwin, Michael W. Senko, Neil L. Kelleher, Jared O. Kafader
Abstract
Collision cross section (CCS) measurements determined by ion mobility spectrometry (IMS) provide useful information about gas-phase protein structure that is complementary to mass analysis. Methods for determining CCS without a dedicated IMS system have been developed for Fourier transform mass spectrometry (FT-MS) platforms by measuring the signal decay during detection. Individual ion mass spectrometry (I 2 MS) provides charge detection and measures ion lifetimes across the length of an FT-MS detection event. By tracking lifetimes for entire ion populations, we demonstrate simultaneous determination of charge, mass, and CCS for proteins and complexes ranging from ∼8 to ∼232 kDa.