ION MOBILITY SPECTROMETER COMPRISING TWO DRIFT CHAMBERS

摘要

An ion mobility spectrometer has two drift chambers (11) and (12) and a common, doped reaction region (2). Each drift chamber includes an ion modifier (14) and (24), such as one that fragments the doped ions by a high electrical field. One of the drift chambers (11) is doped and the other (12) is undoped. In this way, the dopant adducts are removed by the modification process bVt then recombine with dopant only in the doped chamber.(11) so that different outputs are produced by the two drift chambers.