Estimation of activation energy from the survival yields: Fragmentation study of leucine enkephalin and polyethers by tandem mass spectrometry

Ákos Kuki, Ghazaleh Shemirani, Lajos Nagy, Borbála Antal, Miklós Zsuga, Sándor Kéki

Research output: Contribution to journalArticle

9 Citations (Scopus)


A simple collision model for multiple collisions occurring in quadrupole type mass spectrometers was derived and tested with leucine enkaphalin a common mass spectrometric standard with well-characterized properties. Implementation of the collision model and Rice-Ramsperger-Kassel-Marcus (RRKM) algorithm into a spreadsheet software allowed a good fitting of the calculated data to the experimental survival yield (SY) versus collision energy curve. In addition, fitting also ensured to estimate the efficiencies of the kinetic to internal energy conversion for Leucine enkephalin in quadrupole-time-of-flight and triple quadrupole instruments. It was observed that the experimental SY versus collision energy curves for the leucine enkephalin can be described by the Rice-Ramsperger-Kassel (RRK) formalism by reducing the total degrees of freedom (DOF) to about one-fifth. Furthermore, this collision model with the RRK formalism was used to estimate the critical energy (Eo ) of lithiated polyethers, including polyethylene glycol (PEG), polypropylene glycol (PPG), and polytetrahydrofurane (PTHF) with degrees of freedom similar to that of leucine enkephalin. Applying polyethers with similar DOF provided the elimination of the effect of DOF on the unimolecular reaction rate constant. The estimated value of Eo for PEG showed a relatively good agreement with the value calculated by high-level quantum chemical calculations reported in the literature. Interestingly, it was also found that the Eo values for the studied polyethers were similar.

Original languageEnglish
Pages (from-to)1064-1071
Number of pages8
JournalJournal of the American Society for Mass Spectrometry
Issue number7
Publication statusPublished - Jul 1 2013


  • Collision-induced dissociation
  • Leucine enkephalin
  • Multiple collisions
  • Polyethers
  • RRK and RRKM model
  • Tandem mass spectrometry

ASJC Scopus subject areas

  • Structural Biology
  • Spectroscopy

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