Journal of The American Society for Mass Spectrometry

, Volume 24, Issue 9, pp 1366–1375 | Cite as

Fragmentation of Neutral Amino Acids and Small Peptides by Intense, Femtosecond Laser Pulses

  • Martin J. Duffy
  • Orla Kelly
  • Christopher R. Calvert
  • Raymond B. King
  • Louise Belshaw
  • Thomas J. Kelly
  • John T. Costello
  • David J. Timson
  • William A. Bryan
  • Thomas Kierspel
  • I. C. Edmond Turcu
  • Cephise M. Cacho
  • Emma Springate
  • Ian D. Williams
  • Jason B. GreenwoodEmail author
Research Article


High power femtosecond laser pulses have unique properties that could lead to their application as ionization or activation sources in mass spectrometry. By concentrating many photons into pulse lengths approaching the timescales associated with atomic motion, very strong electric field strengths are generated, which can efficiently ionize and fragment molecules without the need for resonant absorption. However, the complex interaction between these pulses and biomolecular species is not well understood. To address this issue, we have studied the interaction of intense, femtosecond pulses with a number of amino acids and small peptides. Unlike previous studies, we have used neutral forms of these molecular targets, which allowed us to investigate dissociation of radical cations without the spectra being complicated by the action of mobile protons. We found fragmentation was dominated by fast, radical-initiated dissociation close to the charge site generated by the initial ionization or from subsequent ultrafast migration of this charge. Fragments with lower yields, which are useful for structural determinations, were also observed and attributed to radical migration caused by hydrogen atom transfer within the molecule.

Key words

Ion activation Non-statistical dissociation Femtosecond laser induced dissociation Femtosecond laser ionization Radical induced dissociation Charge migration Peptide sequencing Time of flight 



The authors acknowledge support for this work by the Leverhulme Trust, STFC through access to the Artemis Laser Facility, and EPSRC through the STFC Laser Loan Pool. C.R.C. acknowledges support from EPSRC through the Postdoctoral Fellowship Programme (grant number EP/H027319/1). L.B. and M.J.D. acknowledge the support of the Department of Employment and Learning, Northern Ireland. T.J.K. and J.T.C. acknowledge support from Science Foundation Ireland. The authors also acknowledge the technical assistance provided by Phil Rice at the Artemis Laser Facility.


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Copyright information

© American Society for Mass Spectrometry 2013

Authors and Affiliations

  • Martin J. Duffy
    • 1
  • Orla Kelly
    • 1
  • Christopher R. Calvert
    • 1
  • Raymond B. King
    • 1
  • Louise Belshaw
    • 1
  • Thomas J. Kelly
    • 2
  • John T. Costello
    • 2
  • David J. Timson
    • 3
  • William A. Bryan
    • 4
  • Thomas Kierspel
    • 5
    • 6
  • I. C. Edmond Turcu
    • 5
  • Cephise M. Cacho
    • 5
  • Emma Springate
    • 5
  • Ian D. Williams
    • 1
  • Jason B. Greenwood
    • 1
    Email author
  1. 1.Centre for Plasma Physics, School of Mathematics and PhysicsQueen’s University BelfastBelfastUK
  2. 2.National Centre for Plasma Science and Technology, School of Physical SciencesDublin City UniversityDublinRepublic of Ireland
  3. 3.School of Biological SciencesQueen’s University BelfastBelfastUK
  4. 4.Department of PhysicsSwansea UniversitySwanseaUK
  5. 5.STFC Rutherford Appleton LaboratoryDidcotUK
  6. 6.Center for Free‐Electron Laser Science, DESYHamburgGermany

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