Patent ID: 7858931

Claim:
A method for the mass-selective transport of ions, especially in a mass spectrometer, comprising the steps of: provision of the ions with an ion source apparatus at a predetermined reference time, the ions having a predetermined initial kinetic energy; moving the ions on a movement path on which a plurality of electrodes are arranged; and loading the electrodes successively with acceleration voltage pulses under the electrical field effects of which the ions experience a mass-dependent change of a speed, comprising the steps of: generating a first acceleration voltage with a sign opposite a charge of the target ions; continuously loading one of the electrodes approached by the target ions with the first acceleration voltage; generating a second acceleration voltage with a sign the same as the charge of the target ions; and continuously loading each time one of the electrodes from which the target ions depart with the second acceleration voltage, wherein: the speed of the ions along the movement path is determined by the initial kinetic energy, a mass-charge ratio of the ions and the electrical field effects at the individual electrodes, said successive loading of the electrodes is coordinated in time with the reference time, and the duration of the acceleration voltage pulses is changed during said successive loading along the movement path in such a manner that target ions with a pre-determined target mass are accelerated along the movement path.