Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, 4-3-11 Takeda, Kofu, Yamanashi 400-8511, Japan.
J Am Soc Mass Spectrom. 2011 Dec;22(12):2108-14. doi: 10.1007/s13361-011-0253-2. Epub 2011 Oct 12.
This is a follow-up paper of our previous report on an ion source, which was operated at an operating pressure higher than the atmospheric pressure. Besides having more working gas for desolvation, the reduction of mean free path of electrons in a higher pressure environment increases the threshold voltage for gaseous breakdown, thus enabling a stable electrospray for the sample solution with high surface tension without the occurrence of electric discharge. In our previous work, the ion source was not coupled directly to the mass spectrometer and significant amount of ions were lost before entering the vacuum of the mass spectrometer. In this paper, we report the new design of our second prototype in which, by using a modified ion transport capillary, the pressurized ESI ion source was coupled directly to the first pumping stage of the mass spectrometer without additional modification on the vacuum pumping system. Demonstrations of the new ion source on the sensitive detection of native proteins from aqueous solution in both positive and negative ion modes are presented.
这是我们之前关于一种工作在高于大气压的离子源的后续报告。除了有更多的工作气体用于解吸之外，在更高压力环境中电子的平均自由程的减少增加了气体击穿的阈值电压，从而使具有高表面张力的样品溶液能够稳定地进行电喷雾，而不会发生放电。在我们之前的工作中，离子源没有直接与质谱仪耦合，在进入质谱仪的真空环境之前，大量离子会损失。在本文中，我们报告了我们的第二个原型的新设计，其中通过使用改进的离子传输毛细管，将加压的 ESI 离子源直接耦合到质谱仪的第一级抽气系统，而无需对真空抽气系统进行额外的修改。本文展示了该新型离子源在正离子模式和负离子模式下对水溶液中天然蛋白质的灵敏检测。
