Journal of the American Society for Mass Spectrometry

, Volume 4, Issue 2, pp 106–110

Fe+ chemical ionization of peptides


  • J. Paul Speir
    • Department of ChemistryUniversity of Georgia
  • Greg S. Gorman
    • Department of ChemistryUniversity of Georgia
  • I. Jonathan Amster
    • Department of ChemistryUniversity of Georgia

DOI: 10.1016/1044-0305(93)85065-6

Cite this article as:
Speir, J.P., Gorman, G.S. & Amster, I.J. J Am Soc Mass Spectrom (1993) 4: 106. doi:10.1016/1044-0305(93)85065-6


Laser-desorbed peptide neutral molecules were allowed to react with Fe+ in a Fourier transform mass spectrometer, using the technique of laser desorption/chemical ionization. The Fe+ ions are formed by laser ablation of a steel target, as well as by dissociative charge-exchange ionization of ferrocene with Ne+. Prior to reaction with laser-desorbed peptide molecules, Fe+ ions undergo 20–100 thermalizin collisions with xenon to reduce the population of excited-state metal ion species. The Fe+ ions that have not experienced thermalizing collisions undergo charge exchange with peptide molecules. Iron ions that undergo thermalizing collisions before they are allowed to react with peptides are found to undergo charge exchange and to form adduct species [M + Fe+] and fragment ions that result from the loss of small, stable molecules, such as H2O, CO, and CO2, from the metal ion-peptide complex.

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© American Society for Mass Spectrometry 1993