Publication Details
Restrained Ion Population Transfer: A Novel Ion Transfer Method for Mass Spectrometry.Citation
Kaiser NK, G Skulason, CR Weisbrod, S Wu, K Zhang, DC Prior, MA Buschbach, GA Anderson, and JE Bruce.2008."Restrained Ion Population Transfer: A Novel Ion Transfer Method for Mass Spectrometry."Rapid Communications in Mass Spectrometry 22(12):1955-1964.
Abstract
With modern Fourier transform ion cyclotron resonance (ICR) mass spectrometers, ions are created and accumulated exterior to the mass analyzer. The ion accumulation event takes place in a region of higher pressure which allows ions to be thermally cooled before being given kinetic energy and accelerated toward the ICR cell where they are to be decelerated and re-trapped. When gated trapping is used to collect ions in the ICR cell for analysis, mass discrimination can occur due to time-of-flight effects. Also, trapping ions with large axial kinetic energy can decrease the performance of the ICR instrument when compared to the analysis of thermally-cooled ions located at the trap center. Therefore, it is desirable to limit the energy imparted in the ions within the ICR cell as well as minimize time-of-flight effects. The approach presented here for ion transfer called restrained ion population transfer or RIPT provides complete axial control of an ion population throughout the entire transfer sequence from the accumulation region to the ICR cell. This is accomplished by utilization of a number of quadrupole segments arranged in series with independent control of the dc bias voltage applied to each segment of the quadrupole ion guide. This approach circumvents problems associated with time-of-flight effects and minimizes the energy imparted to the ions allowing transfer of the cooled ion packet from the ion accumulation region to the ICR cell. Initial data are presented to illustrate feasibility of restrained ion population transfer. RIPT was also modeled with SIMION 7.0 and simulation results that support our feasibility studies of the ions transfer process are presented.
