Patent ID: 8237118

Claim:
An apparatus for separating ions, comprising: at least one ion inlet; an ion outlet; an outer electrode comprising an inner concave partial ovoidal surface; an inner electrode comprising an outer convex partial ovoidal surface, said convex partial ovoidal surface concentric with said concave partial ovoidal surface, said convex surface's dimensions being less than said concave surface's dimensions providing a nearly constant displacement between said convex surface and said concave surface and wherein the volume between said concave surface and said convex surface defines an analyzer region extending between said at least one ion inlet and said ion outlet; an electrical contact on at least one of said outer electrode and said inner electrode for applying a compensation voltage to said outer electrode and said inner electrode, and an electrical contact on the other of said outer electrode and said inner electrode for applying an asymmetric waveform to at least one of said outer electrode and said inner electrode 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 in one or more equivalent curved paths imposed by the shape of said partial ovoidal surfaces defining said analyzer region; and a base plate comprising a material wherein said electrodes are fixed and electrically insulated from each other.