In one aspect, a mass spectrometer is disclosed, which comprises an ion trap having a plurality of electrodes arranged in a multipole configuration so as to provide an inlet for receiving ions along a longitudinal axis into a space between the electrodes, where at least one of the plurality of electrodes comprises a passageway through which ions can be extracted radially from the ion trap. The electrodes are configured for application of one or more RF voltages thereto for providing radial confinement of the ions, and a DC voltage source configured to apply a dipolar DC voltage pulse across said at least one electrode and an opposed electrode for causing radial extraction of at least a portion of said ions from said ion trap through said passageway.