An ion trap is disclosed comprising a plurality of elongate electrodes aligned with one another and with a central longitudinal axis along respective longitudinal axes and that are spaced apart from one another and disposed about a central longitudinal axis to form a quadrupole. The ion trap further comprises an elongate electrode that is aligned with and disposed along the central longitudinal axis, and circuitry coupled to the outer electrodes is suitable for driving the central and outer electrodes to selectively trap of ions within a region defined between the central electrode and the outer.