Experimental verification of an improved prefilter model

The experimental verification of predictions of a new simulation model of quadrupole mass filters is presented. Computer calculations show that the transmission of the prefilter-QMS system is periodical as a function of the prefilter length. The periodicity of the transmission is independent of the mass number of ions of equal velocity. Experimental proof of the simulation has been produced for low mass numbers and a more difficult procedure is required for higher masses (m/z > 100). This is realized with a closed ion source and tandem quadrupole mass spectrometer arrangement. Experimental results prove the mass-independent behaviour predicted by the model.