An ion trap-ion mobility-time of flight mass spectrometer with three ion sources for ion/ion reactions

  • Qin Zhao
  • Matthew W. Soyk
  • Gregg M. Schieffer
  • Katrin Fuhrer
  • Marc M. Gonin
  • R. S. Houk
  • Ethan R. Badman
Articles

DOI: 10.1016/j.jasms.2009.04.014

Cite this article as:
Zhao, Q., Soyk, M.W., Schieffer, G.M. et al. J Am Soc Mass Spectrom (2009) 20: 1549. doi:10.1016/j.jasms.2009.04.014

Abstract

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 ∼880 Å2. 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.

Download to read the full article text

Supplementary material

13361_2011_200801549_MOESM1_ESM.jpg (231 kb)
Supplementary material, approximately 236 KB.
13361_2011_200801549_MOESM2_ESM.rtf (16 kb)
Supplementary material, approximately 16 KB.

Copyright information

© American Society for Mass Spectrometry 2009

Authors and Affiliations

  • Qin Zhao
    • 1
  • Matthew W. Soyk
    • 1
  • Gregg M. Schieffer
    • 1
  • Katrin Fuhrer
    • 3
  • Marc M. Gonin
    • 3
  • R. S. Houk
    • 2
  • Ethan R. Badman
    • 1
  1. 1.Department of ChemistryIowa State UniversityAmesUSA
  2. 2.Ames Laboratory, U.S. Department of EnergyIowa State UniversityAmesUSA
  3. 3.Tofwerk AGThunSwitzerland
  4. 4.Hoffmann-La Roche Inc.Nonclinical SafetyNutleyUSA