title: Controlling charge states of large ions.
abstract: The charge state of ions produced in electrospray ionization (ESI) was reduced in a controlled manner to yield predominantly singly charged species by exposure of the aerosol to a bipolar ionizing gas. Analysis of the resulting ions on an orthogonal time-of-flight mass spectrometer yielded mass spectra greatly simplified compared with conventional ESI spectra. The decreased spectral complexity afforded by the charge reduction facilitates the analysis of mixtures by ESI mass spectrometry.
authors.affiliation: Department of Chemistry, University of Wisconsin, Madison, WI 53706-1396, USA.
authors.forename: M
authors.initials: M
authors.lastname: Scalf
authors.forename: M S
authors.initials: MS
authors.lastname: Westphall
authors.forename: J
authors.initials: J
authors.lastname: Krause
authors.forename: S L
authors.initials: SL
authors.lastname: Kaufman
authors.forename: L M
authors.initials: LM
authors.lastname: Smith
mesh_terms: D000336:Aerosols; D003574:Cytochrome c Group / Q000032:analysis; D004563:Electrochemistry; D007328:Insulin / Q000032:analysis; D007477:Ions; D013058:Mass Spectrometry / Q000295:instrumentation / Q000379:methods; D009841:Oligonucleotides / Q000032:analysis*; D011059:Polonium; D011506:Proteins / Q000032:analysis*; D014452:Ubiquitins / Q000032:analysis
chemical_list: D000336:Aerosols; D003574:Cytochrome c Group; D007328:Insulin; D007477:Ions; D009841:Oligonucleotides; D011506:Proteins; D014452:Ubiquitins; D011059:Polonium