title: A new technique for unbiased external ion accumulation in a quadrupole two-dimensional ion trap for electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry.
abstract: External ion accumulation in a two-dimensional (2D) multipole trap has been shown to increase the sensitivity, dynamic range and duty cycle of a Fourier transform ion cyclotron resonance (FTICR) mass spectrometer. However, it is important that trapped ions be detected without significant bias at longer accumulation times in the external 2D multipole trap. With increasing ion accumulation time pronounced m/z discrimination was observed when trapping ions in an accumulation quadrupole. In this work we show that superimposing lower rf-amplitude dipolar excitation over the main rf-field in the accumulation quadrupole results in disruption of the m/z discrimination and can potentially be used to achieve unbiased external ion accumulation with FTICR.
authors.affiliation: Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA 99352, USA.
authors.forename: M E
authors.initials: ME
authors.lastname: Belov
authors.forename: E N
authors.initials: EN
authors.lastname: Nikolaev
authors.forename: K
authors.initials: K
authors.lastname: Alving
authors.forename: R D
authors.initials: RD
authors.lastname: Smith
mesh_terms: D000803:Angiotensin I / Q000032:analysis; D000818:Animals; D001920:Bradykinin / Q000032:analysis; D017357:Cyclotrons; D005583:Fourier Analysis; D006096:Gramicidin / Q000032:analysis; D006736:Horses; D009211:Myoglobin / Q000032:analysis; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
chemical_list: D009211:Myoglobin; D006096:Gramicidin; D000803:Angiotensin I; D001920:Bradykinin