Nanotip Ambient Ionization Mass Spectrometry
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- 作者：Zhenpeng Zhou ; Jae Kyoo Lee ; Samuel C. Kim ; Richard N. Zare
- 刊名：Analytical Chemistry
- 出版年：2016
- 出版时间：May 17, 2016
- 年：2016
- 卷：88
- 期：10
- 页码：5542-5548
- 全文大小：509K
- 年卷期：0
- ISSN：1520-6882
文摘
A method called nanotip ambient ionization mass spectrometry (NAIMS) is described, which applies high voltage between a tungsten nanotip and a metal plate to generate a plasma in which ionized analytes on the surface of the metal plate are directed to the inlet and analyzed by a mass spectrometer. The dependence of signal intensity is investigated as a function of the tip-to-plate distance, the tip size, the voltage applied at the tip, and the current. These parameters are separately optimized to achieve sensitivity or high spatial resolution. A partially observable Markov decision process is used to achieve a stabilized plasma as well as high ionization efficiency. As a proof of concept, the NAIMS technique has been applied to phenanthrene and caffeine samples for which the limits of detection were determined to be 0.14 fmol for phenanthrene and 4 amol for caffeine and to a printed caffeine pattern for which a spatial resolution of 8 ± 2 μm, and the best resolution of 5 μm, was demonstrated. The limitations of NAIMS are also discussed.