Patent ID: 8440968
Filing Date: 2013-05-14
Classification: G01N

Abstract:
1. An ion-mobility analyser comprising: an upper series of electrodes; a lower series of electrodes disposed parallel to the upper series of electrodes; a first plurality of intermediate electrodes disposed between the upper and lower series of electrodes; a second plurality of intermediate electrodes disposed between the upper and lower series of electrodes and spaced from the first plurality of intermediate electrodes, wherein the upper and lower series of electrodes and the first and second plurality of intermediate electrodes define an ion pathway through which ions travel during operation of the analyser; a gas at a sub-ambient pressure in the ion pathway; and a voltage source configured to apply simultaneously both: (i) an asymmetric voltage waveform to at least some of said electrodes so that ions become separated in a radial direction according to their rate of change of ion mobility with electric field strength; and (ii) a symmetric voltage to, one or more transient DC voltages to, or a linear axial voltage gradient across at least some of said electrodes so that ions become separated in an axial direction according to their ion mobility.