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 Mar;22(3):539-44. doi: 10.1007/s13361-010-0058-8. Epub 2011 Feb 1.
High pressure electrospray ionization mass spectrometry has been performed by pressurizing a custom made ion source chamber with compressed air to a pressure higher than the atmospheric pressure. The ion source was coupled to a commercial time-of-flight mass spectrometer using a nozzle-skimmer arrangement. The onset voltage for the electrospray of aqueous solution was found to be independent on the operating pressure. The onset voltage for the corona discharge, however, increased with the rise of pressure following the Paschen's law. Thus, besides having more working gas for the desolvation process, gaseous breakdown could also be avoided by pressurizing the ESI ion source with air to an appropriate level. Stable electrospray ionization has been achieved for the sample solution with high surface tension such as pure water in both positive and negative ion modes. Fragmentation of labile compounds during the ionization process could also be reduced by optimizing the operating pressure of the ion source.
采用压缩空气将定制的离子源室加压至高于大气压的压力，实现了高压电喷雾电离质谱法。使用喷嘴-文丘里管装置将离子源与商业飞行时间质谱仪耦合。发现水相溶液的电喷雾起始电压与操作压力无关。然而，电晕放电的起始电压随着压力的升高而遵循巴申定律增加。因此，通过将 ESI 离子源用空气加压至适当水平，除了为去溶剂化过程提供更多的工作气体外，还可以避免气体击穿。在正离子和负离子模式下，对于表面张力较高的样品溶液（如纯水），均可实现稳定的电喷雾电离。通过优化离子源的工作压力，还可以减少易分解化合物在电离过程中的碎裂。
