title: Improving liquid chromatography-mass spectrometry sensitivity using a subambient pressure ionization with nanoelectrospray (SPIN) interface.
abstract: In this work, the subambient pressure ionization with nanoelectrospray (SPIN) ion source and interface, which operates at ~15-30 Torr, is demonstrated to be compatible with gradient reversed-phase liquid chromatography-MS applications, exemplified here with the analysis of complex samples (a protein tryptic digest and a whole cell lysate). A low liquid chromatographic flow rate (100-400 nL/min) allowed stable electrospray to be established while avoiding electrical breakdown. Efforts to increase the operating pressure of the SPIN source relative to previously reported designs prevented solvent freezing and enhanced charged cluster/droplet desolvation. A 5- to 12-fold improvement in sensitivity relative to a conventional atmospheric pressure nanoelectrospray ionization (ESI) source was obtained for detected peptides.
authors.affiliation: Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, USA.
authors.forename: Keqi
authors.initials: K
authors.lastname: Tang
authors.forename: Jason S
authors.initials: JS
authors.lastname: Page
authors.forename: Ioan
authors.initials: I
authors.lastname: Marginean
authors.forename: Ryan T
authors.initials: RT
authors.lastname: Kelly
authors.forename: Richard D
authors.initials: RD
authors.lastname: Smith
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000032:analysis / Q000737:chemistry; D002853:Chromatography, Liquid / Q000379:methods*; D008969:Molecular Sequence Data; D036103:Nanotechnology / Q000295:instrumentation* / Q000379:methods*; D010446:Peptide Fragments / Q000032:analysis / Q000737:chemistry; D011312:Pressure; D012680:Sensitivity and Specificity; D020592:Shewanella; D021241:Spectrometry, Mass, Electrospray Ionization / Q000295:instrumentation* / Q000379:methods*
chemical_list: D001426:Bacterial Proteins; D010446:Peptide Fragments