Simulation of ion trajectories through the mass filter of a quadrupole mass spectrometer

The paper describes the development of a computer program designed to simulate the performance of the mass filter in an ideal quadrupole mass spectrometer (QMS). The simulation program provides flexible input parameters to allow the user to investigate the ion trajectories and transmission efficiency for different operating conditions. The program is used to analyse the change in QMS resolution with the number of RF cycles, DC voltage, RF voltage magnitude and phase angle. The angle at which ions enter the mass filter is shown to be significant and the effect of RF phase on transmission probability through the filter is seen to be critical. A comparison of the simulation with experimental QMS results shows excellent agreement