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Soft‐sputtering of insulin films in argon‐cluster secondary ion mass spectrometry
Author(s) -
Oshima Shohei,
Kashihara Ippei,
Moritani Kousuke,
Inui Norio,
Mochiji Kozo
Publication year - 2011
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.4959
Subject(s) - chemistry , sputtering , argon , mass spectrometry , ion , cluster (spacecraft) , static secondary ion mass spectrometry , chromatography , secondary ion mass spectrometry , analytical chemistry (journal) , nanotechnology , thin film , organic chemistry , computer science , programming language , materials science
In secondary ion mass spectrometry (SIMS) of organic substances, the dissociation of the sample molecules is crucial. We have developed SIMS equipment capable of bombardment, where the primary ions are argon cluster ions with kinetic energy per atom controllable down to 1 eV. We previously reported the detection of intact ions of insulin and cytochrome C using this equipment. In this paper, we present a detailed characterization of the emission of secondary ions from insulin, focusing on the difference in secondary ion yield between intact ions and fragment ions by varying the incident angle of the cluster ions. The emission intensity of the intact ions was changed drastically due to the exposed dosage and incident angle of the cluster ions in contrast to the fragment ions. We discuss these results based on the manner in which the argon‐cluster ions collide with the organic solid. Copyright © 2011 John Wiley & Sons, Ltd.