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Energy partitioning in the surface‐induced dissociation of linear and cyclic protonated peptides at an organic surface
Author(s) -
Schultz D. G.,
Lim H.,
Garbis S.,
Hanley L.
Publication year - 1999
Publication title -
journal of mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 1076-5174
DOI - 10.1002/(sici)1096-9888(199903)34:3<217::aid-jms797>3.0.co;2-r
Subject(s) - chemistry , kinetic energy , ion , dissociation (chemistry) , protonation , collision induced dissociation , atomic physics , polyatomic ion , scattering , mass spectrometry , analytical chemistry (journal) , chemical physics , tandem mass spectrometry , organic chemistry , chromatography , optics , physics , quantum mechanics
Full understanding of the surface‐induced dissociation(SID) of biological ions requires the determination of theenergy channeling into the surface and the scattered ion kinetic andinternal energies. Parent and fragment ion kinetic energydistributions were measured for five peptide ions scattered off ahexanethiolate monolayer on Au(111). Singly protonated ionsof triglycine, tetraglycine, cyclo(Pro‐Gly),cyclo(His‐Phe) and tentoxin were formed byelectrospray ionization and scattered at 15–55 eV collisionenergies off the organic surface. The scattered parent ion kineticenergies were 24% of the incident ion energy for the linearpeptides, 21% for the cyclic dipeptides and 17% for thefour‐peptide ring. These results suggest that ion sizeand/or structure influences the scattered kinetic energy. Usingthese values and assuming an average internal excitation efficiencyof 17%, it is estimated that the final internal energy givento the surface is 59–66% of the initial collisionenergy. This energy transfer to the surface is very close to thatpreviously estimated for a host of smaller polyatomic ions scatteredfrom similar organic targets. However, comparison with small ion SIDshows that the peptides leave the surface with a wider distributionof kinetic energies. Finally, the measured kinetic energydistributions show that the fragment ions for a given peptide leavethe surface with a common velocity, suggesting that dissociationoccurs away from the surface. All fragments were found to result fromnon‐reactive, inelastic scattering off the organic surface.Copyright © 1999 John Wiley & Sons, Ltd.