Atmospheric Pressure Ionization in a Miniature Mass Spectrometer

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• 作者：Brian C. Laughlin ; Christopher C. Mulligan ; and R. Graham Cooks
• 刊名：Analytical Chemistry
• 出版年：2005
• 出版时间：May 1, 2005
• 年：2005
• 卷：77
• 期：9
• 页码：2928 - 2939
• 全文大小：316K
• 年卷期：v.77,no.9(May 1, 2005)
• ISSN：1520-6882

文摘

A miniature cylindrical ion trap mass spectrometer featuring an atmospheric pressure interface allowing atmospheric pressure chemical ionization and electrosprayionization is described together with its analytical performance characteristics. The vacuum system, ion optics,mass analyzer, control electronics system, and detectionsystem have all been designed and built in-house. Thedesign is based upon a three-stage, differentially pumpedvacuum system with the instrument capable of beinginterfaced to many types of atmospheric pressure ionization sources. Ions are transferred through home-built ionoptics, and instrument control is achieved through custom-designed electronics and LabView control software. Corona discharge ionization and electrospray ionizationsources are implemented and used to allow the analysisof both gaseous- and solution-phase samples during thecharacterization of the instrument. An upper mass/chargelimit of ~450 Th with unit resolution was achieved usinga 2.5-mm-internal radius cylindrical ion trap as the massanalyzer. The specificity of the instrument can be increased by employing the MS/MS capabilities of the iontrap and has been demonstrated for nitrobenzene. Limitsof detection for the trace analysis in air of the chemicalwarfare agent simulant methyl salicylate (1.24 ppb) andfor nitrobenzene (629 pptr) are achieved. The dynamicrange of the instrument is currently limited to ~2 ordersof magnitude by saturation of the detection electronics.Isolation and collision-induced dissociation efficienciesin MS/MS experiments both greater than 50% are reported. Electrospray/nanospray data are presented onsolutions including 100 (D,L)-arginine, 10 M (-)-ephedrine, and 10 M lomefloxacin.