Design and implementation of MIR F-Disc: An electrodynamic ion manipulation device

Effectively focusing and transmitting ions from near atmospheric region ion sources to high vacuum mass analyzers is a key factor that affects the sensitivity and dynamic range in mass spectrometry. To improve the efficiency of ion transmission under limit vacuum conditions, a novel electrodynamic ion transmission device (MIR F-Disc) was developed and characterized in this work. An ion funnel was divided into four equal columns, all of which formed one pole in quadrupole field in the axial direction, thereby forming a coupling between the quadrupole field and the ion funnel electric field. The MIR F-Disc concept was verified by simulations, the optimal transmission efficiency was 70%–80%. Additionally, the MIR F-Disc was used as an atmospheric pressure ionization introduction orifice for a lab-built time-of-flight mass spectrometer. Three different modes of radio frequency (RF) and direct current (DC) electrical field applications were tested. The transmission efficiencies for peptides and proteins were typically over 70% of the total incoming currents from capillary, which was consistent with the simulation results. MIR F-Disc could provide ion fragmentation function under certain operating conditions with efficiency of over 80%. Taken together, the smaller size (less than 3 cm length with 0.7 mm orifice) and significant ion transmission efficiency as well as the ion fragmentation ability make the MIR F-Disc more suitable for mini-mass spectrometry.