Use of Interrupted Helium Flow in the Analysis of Vapor Samples with Flowing Atmospheric-Pressure Afterglow-Mass Spectrometry

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• 作者：Andrew P. Storey ; Offer M. Zeiri…
• 关键词：Ambient ionization ; Ion sources ; Vapor analysis ; Gas ; flow dynamics ; Helium conservation
• 刊名：Journal of The American Society for Mass Spectrometry
• 出版年：2017
• 出版时间：February 2017
• 年：2017
• 卷：28
• 期：2
• 页码：263-269
• 全文大小：
• 刊物主题：Analytical Chemistry; Biotechnology; Organic Chemistry; Proteomics; Bioinformatics;
• 出版者：Springer US
• ISSN：1879-1123
• 卷排序：28

文摘

The flowing atmospheric-pressure afterglow (FAPA) source was used for the mass-spectrometric analysis of vapor samples introduced between the source and mass spectrometer inlet. Through interrupted operation of the plasma-supporting helium flow, helium consumption is greatly reduced and dynamic gas behavior occurs that was characterized by schlieren imaging. Moreover, mass spectra acquired immediately after the onset of helium flow exhibit a signal spike before declining and ultimately reaching a steady level. This initial signal appears to be due to greater interaction of sample vapor with the afterglow of the source when helium flow resumes. In part, the initial spike in signal can be attributed to a pooling of analyte vapor in the absence of helium flow from the source. Time-resolved schlieren imaging of the helium flow during on and off cycles provided insight into gas-flow patterns between the FAPA source and the MS inlet that were correlated with mass-spectral data.