Orthogonal Injection Ion Funnel Interface Providing Enhanced Performance for Selected Reaction Monitoring-Triple Quadrupole Mass Spectrometry

The electrodynamic ion fining 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 5 developed: and characterized. An orthogonal ion injection inlet and a repeller plate electrode was used to direct ions to ail ion funnel HPIF at a, pressure of 9-1,0 Torn Key factors for the HPIF performance-chatacterized 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: