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Secondary ion yields for vacuum‐type electrospray droplet beams measured with a triple focus time‐of‐flight analyzer
Author(s) -
Ninomiya Satoshi,
Sakai Yuji,
Watanabe Ryo,
Sogou Mauo,
Miyayama Takuya,
Sakai Daisuke,
Watanabe Katsumi,
Chen Lee Chuin,
Hiraoka Kenzo
Publication year - 2016
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.7703
Subject(s) - chemistry , secondary ion mass spectrometry , ion , mass spectrometry , electrospray ionization , ion beam , analytical chemistry (journal) , electrospray , ion source , time of flight , mass spectrum , ion beam deposition , time of flight mass spectrometry , maldi imaging , ion gun , ionization , chromatography , matrix assisted laser desorption/ionization , desorption , organic chemistry , adsorption
Rationale We previously developed a massive cluster ion beam gun for secondary ion mass spectrometry (SIMS) in which the primary beam source is a vacuum electrospray. The secondary ion yields produced by this method had not yet been measured with a commercial time‐of‐flight (TOF) secondary ion mass spectrometer, and the ionization performance was unknown. Methods A vacuum‐type electrospray droplet ion gun was connected to a triple‐focus TOF analyzer. The flight time of the secondary ions was measured using a sample‐bias pulsing method, because a short pulse of the electrospray droplet beam could not be obtained. The secondary ion yields of an amino acid sample produced by the electrospray droplet beams and atomic Ga ion beams were compared. Results TOF secondary ion spectra were measured for the amino acid and peptide samples with a mass resolution of ~500 using the sample‐bias pulsing method. The secondary ion yield of the amino acid sample produced with the 10 kV vacuum‐type electrospray droplet beams was much higher than that produced by 10 kV Ga ion beams. In addition, the secondary ion yields for the peptide sample and amino acid samples were almost similar. Conclusions This is the first report on secondary ion yields produced with vacuum‐type electrospray droplet ion beams and measured with a semi‐commercial TOF analyzer. The enhancement of secondary ion yields, in particular for relatively high‐mass molecules, would be very useful in the SIMS analysis of a wide variety of biological samples. Copyright © 2016 John Wiley & Sons, Ltd.