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Matrix‐free detection of intact ions from proteins in argon‐cluster secondary ion mass spectrometry
Author(s) -
Mochiji Kozo,
Hashinokuchi Michihiro,
Moritani Kousuke,
Toyoda Noriaki
Publication year - 2009
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.3922
Subject(s) - chemistry , ion , kinetic energy , fragmentation (computing) , biomolecule , mass spectrometry , dissociation (chemistry) , argon , sputtering , analytical chemistry (journal) , collision induced dissociation , fast atom bombardment , cluster (spacecraft) , matrix (chemical analysis) , atom (system on chip) , molecule , tandem mass spectrometry , chromatography , nanotechnology , thin film , organic chemistry , biochemistry , physics , materials science , quantum mechanics , computer science , embedded system , programming language , operating system
In the secondary ion mass spectrometry (SIMS) of organic substances, the molecular weight of the intact ions currently detectable is at best only as high as 1000 Da, which for all practical purposes prevents the technique from being applied to biomaterials of higher mass. We have developed SIMS instrumentation in which the primary ions were argon cluster ions having a kinetic energy per atom, controlled down to 1 eV. On applying this instrumentation to several peptides and proteins, the signal intensity of fragment ions was decreased by a factor of 10 2 when the kinetic energy per atom was decreased below 5 eV; moreover, intact ions of insulin (molecular weight (MW): 5808) and cytochrome C (MW: 12 327) were detected without using any matrix. These results indicate that fragmentation can be substantially suppressed without sacrificing the sputter yield of intact ions when the kinetic energy per atom is decreased to the level of the target's dissociation energy. This principle is fully applicable to other biomolecules, and it can thus be expected to contribute to applications of SIMS to biomaterials in the future. Copyright © 2009 John Wiley & Sons, Ltd.