Patent ID: 8049167

Claim:
An apparatus for separating ions, comprising: at least one ion inlet; at least one ion outlet; a first electrode comprising a surface; a second electrode comprising a surface; at least one porous spacer, wherein said first and second electrodes have a constant displacement between said surfaces of said first and second electrodes and electrical insulating said first electrode from said second electrode, wherein the volume between said surfaces and said at least one spacer define an analyzer region extending between said at least one ion inlet and said at least one ion outlet; an electrical contact on at least one of said first and second electrodes for applying a compensation voltage between said first and second electrodes, and an electrical contact on at least one of said first and second electrodes for applying an asymmetric waveform to at least one of said first and second electrodes wherein during application of said compensation voltage and said asymmetric waveform at least one ion is selectively transmitted through said analyzer region from said at least one ion inlet to said ion outlet; and at least one gas source providing a focusing gas for diffusion through said porous spacers wherein the ions are focused pneumatically by said focusing gas.