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Mass peak profiles for quadrupole mass filter with deformed rod arrangement are calculated to investigate profile defects such as unexpected peak separation and precursor peaks to adversely affect mass spectrometry. In this paper we treat rod deformed arrangement such as rohmbus–positioned rod arrangement and square arrangement with different rod radius. The electrostatic potentials inside such rod arrangements are obtaind as multipole expansions, the coeffcients of which are calculated. Using these expansions, the motion equations of ions are calculated to get the mass peak profiles. The result shows that in the present case no peak separations and no precursor peaks appear. We conclude that rod deformation is not always to have a negative influence on mass peak analysis.

Mass peak profiles for quadrupole mass filter with deformed rod arrangement are calculated to investigate profile defects such as unexpected peak separation and precursor peaks to adversely affect mass spectrometry. In this paper we treat rod deformed arrangement such as rohmbus–positioned rod arrangement and square arrangement with different rod radius. The electrostatic potentials inside such rod arrangements are obtaind as multipole expansions, the coeffcients of which are calculated. Using these expansions, the motion equations of ions are calculated to get the mass peak profiles. The result shows that in the present case no peak separations and no precursor peaks appear. We conclude that rod deformation is not always to have a negative influence on mass peak analysis.

Speeding up using a GPU (Graphic Processing Unit) is studied for computer simulation of mass peak profiles in quadrupole GCMS. Calculations of mass peak profiles are much troublesome because it takes much computing time to get those with a personal computer. In particular, in the case of analyzing unexpected weak sub-peaks such as precursor peaks in the profiles, it is necessary to reduce the statistical variation of the profile curve as possible, so that it need calculate many ion trajectories, probably, up to 10-100 millions. In this study, a GPU is installed into a personal Windows computer, and CUDA parallel computing tecnique is appled to simulate mass peak profiles for a mass filter model with cylindrical rods and pre-rods. Its computation time is compared with one calculated using CPU. The result shows the calculation speed of GPU is at least 10-18 times faster than CPU's.