title: Orthogonal Injection Ion Funnel Interface Providing Enhanced Performance for Selected Reaction Monitoring-Triple Quadrupole Mass Spectrometry.
abstract: The electrodynamic ion funnel facilitates efficient focusing and transfer of charged particles in the higher-pressure regions (e.g., ion source interfaces) of mass spectrometers, thus providing increased sensitivity. An "off-axis" ion funnel design has been developed to reduce the source contamination and interferences from, e.g. ESI droplet residue and other poorly focused neutral or charged particles with very high mass-to-charge ratios. In this study, a dual ion funnel interface consisting of an orthogonal higher pressure electrodynamic ion funnel (HPIF) and an ion funnel trap combined with a triple quadrupole mass spectrometer was developed and characterized. An orthogonal ion injection inlet and a repeller plate electrode was used to direct ions to an ion funnel HPIF at a pressure of 9-10 Torr. Key factors for the HPIF performance characterized included the effects of RF amplitude, the DC gradient, and operating pressure. Compared to the triple quadrupole standard interface more than 4-fold improvement in the limit of detection for the direct quantitative MS analysis of low abundance peptides was observed. The sensitivity enhancement in liquid chromatography selected reaction monitoring (LC-SRM) analyses of low-abundance peptides spiked into a highly complex mixture was also compared with that obtained using both a commercial S-lens interface and an in-line dual-ion funnel interface.
authors.affiliation: Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352, United States.
authors.forename: Tsung-Chi
authors.initials: TC
authors.lastname: Chen
authors.affiliation: Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352, United States.
authors.forename: Thomas L
authors.initials: TL
authors.lastname: Fillmore
authors.affiliation: Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352, United States.
authors.forename: Spencer A
authors.initials: SA
authors.lastname: Prost
authors.affiliation: Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352, United States.
authors.forename: Ronald J
authors.initials: RJ
authors.lastname: Moore
authors.affiliation: Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352, United States.
authors.forename: Yehia M
authors.initials: YM
authors.lastname: Ibrahim
authors.affiliation: Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352, United States.
authors.forename: Richard D
authors.initials: RD
authors.lastname: Smith
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000295:instrumentation; D017022:Flow Injection Analysis / Q000295:instrumentation; D013058:Mass Spectrometry / Q000295:instrumentation; D010455:Peptides / Q000032:analysis*; D011312:Pressure
chemical_list: D010455:Peptides