title: Venturi easy ambient sonic-spray ionization.
abstract: 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.
authors.affiliation: ThoMSon Mass Spectrometry Laboratory, Institute of Chemistry, University of Campinas-UNICAMP, Campinas, SP, Brazil.
authors.forename: Vanessa G
authors.initials: VG
authors.lastname: Santos
authors.forename: Thaís
authors.initials: T
authors.lastname: Regiani
authors.forename: Fernanda F G
authors.initials: FF
authors.lastname: Dias
authors.forename: Wanderson
authors.initials: W
authors.lastname: Romão
authors.forename: Jose Luis Paz
authors.initials: JL
authors.lastname: Jara
authors.forename: Clécio F
authors.initials: CF
authors.lastname: Klitzke
authors.forename: Fernando
authors.initials: F
authors.lastname: Coelho
authors.forename: Marcos N
authors.initials: MN
authors.lastname: Eberlin
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D045304:Cytochromes c / Q000737:chemistry; D005740:Gases / Q000737:chemistry; D007477:Ions; D013058:Mass Spectrometry / Q000379:methods*; D009211:Myoglobin / Q000737:chemistry; D009842:Oligopeptides / Q000737:chemistry; D009930:Organic Chemicals / Q000737:chemistry; D013016:Sound
chemical_list: D005740:Gases; D007477:Ions; D009211:Myoglobin; D009842:Oligopeptides; D009930:Organic Chemicals; D045304:Cytochromes c