Patent ID: 6703609
Filing Date: 2004-03-09
Classification: G01N,H01J

Abstract:
A method for trapping ions comprising the steps of:a) providing a first analyzer region defined by a space between first and second spaced apart electrodes, the first analyzer region being in communication with a first ion inlet and a first ion outlet, the first ion inlet for receiving ions for introduction into the first analyzer region, the first ion outlet for providing ions from the first analyzer region; b) providing a first asymmetric waveform and a first direct-current compensation voltage, to at least one of the first and second electrodes, to form an electric field therebetween, the first asymmetric waveform for effecting a difference in net displacement between the ions in the time of one cycle of the applied first asymmetric waveform; c) setting the first compensation voltage for effecting a first separation of the ions to selectively transmit a first subset of the ions within the first analyzer region; d) providing ions to the first analyzer region; e) coupling ions from the ion outlet of the first analyzer region to a second analyzer; and, f) trapping a selectively transmitted second subset of the ions with the second analyzer to accumulate ions within a trapping region thereof.