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. Greenwood

    Research output: Contribution to journalArticlepeer-review


    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. [Figure not available: see fulltext.]

    Original languageEnglish
    Pages (from-to)1366-1375
    Number of pages10
    JournalJournal of the American Society for Mass Spectrometry
    Issue number9
    Publication statusPublished - 1 Sept 2013


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


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