Ultrafast differential ion mobility spectrometry at extreme electric fields coupled to mass spectrometry.

Microchip-based field asymmetric waveform ion mobility spectrometry (FAIMS) analyzers featuring a grid of 35 mum-wide channels have allowed electric field intensity (E) over 60 kV/cm, or about twice that in previous devices with >0.5 mm gaps. Since the separation speed scales as E4 to E6, these chips filter ions in just approximately 20 micros (or approximately 100-10,000 times faster than "macroscopic" designs), although with reduced resolution.