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Orthogonal time‐of‐flight secondary ion mass spectrometric analysis of peptides using large gold clusters as primary ions
Author(s) -
Tempez Agnès,
Schultz J. A.,
DellaNegra S.,
Depauw J.,
Jacquet D.,
Novikov A.,
Lebeyec Y.,
Pautrat M.,
Caroff M.,
Ugarov M.,
Bensaoula H.,
Gonin M.,
Fuhrer K.,
Woods Amina
Publication year - 2004
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.1342
Subject(s) - chemistry , ion , time of flight , primary (astronomy) , analytical chemistry (journal) , chromatography , organic chemistry , physics , astronomy
Secondary ion mass spectrometry (SIMS) for biomolecular analysis is greatly enhanced by the instrumental combination of orthogonal extraction time‐of‐flight mass spectrometry with massive gold cluster primary ion bombardment. Precursor peptide molecular ion yield enhancements of 1000, and signal‐to‐noise improvements of up to 20, were measured by comparing SIMS spectra obtained using Au + and massive Au 400 4+ cluster primary ion bombardment of neat films of the neuropeptide fragment dynorphin 1–7. Remarkably low damage cross‐sections were also measured from dynorphin 1–7 and gramicidin S during prolonged bombardment with 40 keV Au 400 4+ . For gramicidin S, the molecular ion yield increases slightly as a function of Au 400 4+ beam fluence up to at least 2 × 10 13 Au 400 4+ /cm 2 . This is in marked contrast to the rapid decrease observed when bombarding with ions such as Au 5 + and Au 9 + . When gramicidin S is impinged with Au 5 + , the molecular ion yield decreases by a factor of 10 after a fluence of only 8 × 10 12 ions/cm 2 . Comparison of these damage cross‐sections implies that minimal surface damage occurs during prolonged Au 400 4+ bombardment. Several practical analytical implications are drawn from these observations. Copyright © 2004 John Wiley & Sons, Ltd.