Extend m/z Range of External Ion Injection Into Ion Trap/TOFMS: SIMION Analysis

Ion trap usually serves as a TOF pusher region in ion trap time-of-flight mass spectrometer (IT/TOF), achieving benefits of high duty cycle, MS/MS capability, and high mass resolution. While a short ion trap rod length improves TOF resolution, it limits the mass range in coaxial IT/TOF. Through a computational study based on SIMION simulations, this work systematically investigates the influence of geometric parameters (trap rod length) and voltage parameters (bias DC voltage, end-cap electrode voltage) on the mass range of coaxial IT-TOF systems. By optimizing length of trap rod, over 90% injection efficiency was achieved within a m/z 400-1400 without sacrificing mass resolution. By implementing DC bias voltage adjustments for low-m/z ions and step voltage optimization on end-cap electrodes for high-m/z ions, the simulated mass range is extended to m/z 200-1400 with minimal mass discrimination. All above these findings are derived solely from simulation analysis.