An Ion Trap-Ion Mobility-Time of Flight Mass Spectrometer with Three Ion Sources for Ion/Ion Reactions

TitleAn Ion Trap-Ion Mobility-Time of Flight Mass Spectrometer with Three Ion Sources for Ion/Ion Reactions
Publication TypeJournal Article
Year of Publication2009
AuthorsZhao Q, Soyk MW, Schieffer GM, Fuhrer K, Gonin MM, Houk RS, Badman ER
Journal TitleJournal of the American Society for Mass Spectrometry
Date Published08
ISBN Number1044-0305
Accession NumberISI:000268739900020
Keywordscapture dissoci, collision-induced dissociation, electron-transfer dissociation, electrosprayed ubiquitin ions, gas-phase proteins, native cytochrome-c, proton-transfer reactions, singly charged anions, structural transitions, surface-induced dissociation

This instrument combines the capabilities of ion/ion reactions with ion mobility (IM) and time-of-flight (TOF) measurements for conformation Studies and top-down analysis of large biomolecules. Ubiquitin ions from either of two electrospray ionization (ESI) sources are stored in a three dimensional (3D) ion trap (IT) and reacted with negative ions from atmospheric sampling glow discharge ionization (ASGDI). The proton transfer reaction products are then separated by IM and analyzed via a TOF mass analyzer. In this way, ubiquitin +7 ions are converted to lower charge states down to +1; the ions in lower charge states tend to be in compact conformations with cross sections down to similar to 880 angstrom(2). The duration and magnitude of the ion ejection Pulse on the IT exit and the entrance voltage on the IM drift tube can affect the measured distribution of conformers for ubiquitin +7 and +6. Alternatively, protein ions are fragmented by collision-induced dissociation (CID) in the IT, followed by ion/ion reactions to reduce the charge states of the CID product ions, thus simplifying assignment of charge states and fragments using the mobility-resolved tandem mass spectrum. Instrument characteristics and the use of a new ion trap controller and software modifications to control the entire instrument are described. (J Am Soc Mass Spectrom 2009, 20, 1549-1561) (C) 2009 American Society for Mass Spectrometry

URL<Go to ISI>://000268739900020