Ninomiya Satoshi, Sakai Yuji, Watanabe Ryo, Sogou Mauo, Miyayama Takuya, Sakai Daisuke, Watanabe Katsumi, Chen Lee Chuin, Hiraoka Kenzo
Interdisciplinary Graduate School, University of Yamanashi, 4-3-11 Takeda, Kofu, Yamanashi, 400-8511, Japan.
Clean Energy Research Center, University of Yamanashi, 4-3-11 Takeda, Kofu, Yamanashi, 400-8511, Japan.
Rapid Commun Mass Spectrom. 2016 Oct 30;30(20):2279-84. doi: 10.1002/rcm.7703.
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.
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.
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.
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.
我们之前开发了一种用于二次离子质谱（SIMS）的大型簇离子束枪，其中初级束源是真空电喷雾。该方法产生的二次离子产率尚未用商业飞行时间（TOF）二次离子质谱仪进行测量，其电离性能也未知。
将真空型电喷雾液滴离子枪连接到三聚焦TOF分析仪上。由于无法获得电喷雾液滴束的短脉冲，因此使用样品偏压脉冲法测量二次离子的飞行时间。比较了电喷雾液滴束和原子镓离子束产生的氨基酸样品的二次离子产率。
使用样品偏压脉冲法对氨基酸和肽样品测量了TOF二次离子谱，质量分辨率约为500。10 kV真空型电喷雾液滴束产生的氨基酸样品的二次离子产率远高于10 kV镓离子束产生的产率。此外，肽样品和氨基酸样品的二次离子产率几乎相似。
这是关于用真空型电喷雾液滴离子束产生并使用半商业TOF分析仪测量的二次离子产率的首次报道。二次离子产率的提高，特别是对于相对高质量的分子，在各种生物样品的SIMS分析中将非常有用。版权所有© 2016约翰威立父子有限公司。
