Venturi Easy Ambient Sonic-Spray Ionization

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• 作者：Vanessa G. Santos ; Thai虂s Regiani ; Fernanda F. G. Dias ; Wanderson Roma虄o ; Jose Luis Paz Jara ; Cle虂cio F. Klitzke ; Fernando Coelho ; Marcos N. Eberlin
• 刊名：Analytical Chemistry
• 出版年：2011
• 出版时间：February 15, 2011
• 年：2011
• 卷：83
• 期：4
• 页码：1375-1380
• 全文大小：826K
• 年卷期：v.83,no.4(February 15, 2011)
• ISSN：1520-6882

文摘

The development and illustrative applications of an ambient ionization technique termed Venturi easy ambient sonic-spray ionization (V-EASI) is described. Its dual mode of operation with Venturi self-pumping makes V-EASI applicable to the direct mass spectrometric analysis of both liquid (V_L-EASI) and solid (V_S-EASI) samples. V-EASI is simple and easy to assemble, operating solely via the assistance of a sonic stream of nitrogen or air. The sonic gas stream causes two beneficial and integrated effects: (a) the self-pumping of solutions via the Venturi effect and (b) sonic-spray ionization (SSI) of analytes either in solution or resting on solid surfaces. In its liquid mode, V_L-EASI is applicable to analytes in solution, forming negatively and/or positively charged intact molecular species in a soft fashion with little or no fragmentation. In its solid mode, V_S-EASI relies on Venturi self-pumping of a proper SSI solvent solution in combination with SSI to form a stream of bipolar charged droplets that bombard the sample surface, causing desorption and ionization of the analyte molecules. As for its precursor technique (EASI), V-EASI generates bipolar droplets with considerably lower average charging, which increases selectivity for ionization with high signal-to-noise ratios and clean spectra dominated by single molecular species with minimal solvent ions. V-EASI also operates in a voltage-, heat-, and radiation-free fashion and is therefore free of thermal, electrical, or discharge interferences.