Patent ID: 8872102
Filing Date: 2014-10-28
Classification: G01N,H01J

Abstract:
1. An ion mobility spectrometer instrument comprising: a drift tube partitioned into a plurality of cascaded drift tube segments and ion elimination regions, each of the plurality of drift tube segments defining an ion inlet at one end, an ion outlet at an opposite end and a first distance between the ion inlet and the ion outlet, each of the plurality of ion elimination regions defining a second distance between the ion outlet of a different one of the plurality of drift tube segments and the ion inlet of the next adjacent drift tube segment of the plurality of cascaded drift tube segments, an ion source coupled to one of the plurality of cascaded drift tube segments, one of an ion detector and an ion inlet of at least another ion mobility spectrometer instrument arranged to receive ions exiting the drift tube, a number, M, of electric field activation sources each operatively connected to one or more of the plurality of drift tube segments such that, when activated, each establishes a repulsive electric field in a different one of the first M ion elimination regions and in every following Mth ion elimination region, and also establishes an electric drift field in all remaining ion elimination regions and in all of the plurality of cascaded drift tube segments, and a control circuit to sequentially activate a number of times each of the number, M, of electric field activation sources while deactivating the remaining number, M, of electric field activation sources, with at least one of the M electric field activation sources having a different activation time duration than activation time durations of others of the M electric field activation sources, to thereby cause only ions generated by the ion source that have a predefined ion mobility or range of ion mobilities to traverse the drift tube.