Differential Ion Mobility Spectrometry

Differential Mobility Spectrometry (DMS), also commonly referred to as High Field Asymmetric Waveform Ion Mobility Spectrometry (FAIMS) is a rapidly advancing technology for gas phase ion separation.  (See Vouros Research Group Page for more information)

Electrosprayed ions pass through a drift tube to reach the MS inlet, under viscous flow in a drift gas passing  between electrodes applying short strong positive pulses alternating with long  weak negative pulses (VAC ).  Although the average field is zero, nonlinearity in electrophoretic mobility causes drift.  Applying a DC compensation voltage (Vc) can permit ions to pass.  Both Vc and  VAC  are scanned to produce a 2D plot of ion current. Mass spectra may be acquired of any point on the 2D plot during scanning.