Patent ID: 6713758
Filing Date: 2004-03-30
Classification: B01D,G01N,H01J

Abstract:
An apparatus for separating ions, comprising:an outer electrode comprising an inner curved electrode surface defined by a curve rotated about a central axis and defining an internal cavity, an inlet through a first portion of the inner curved electrode surface for introducing ions and a flow of a carrier gas into an inlet region of the internal cavity proximate the inlet, and an outlet through a second portion of the inner curved electrode surface for extracting ions from an outlet region of the internal cavity proximate the outlet; an inner electrode comprising an outer curved electrode surface, the inner electrode disposed within the internal cavity in a spaced apart arrangement with the outer electrode, the space between the inner electrode and the outer electrode defining an analyzer region extending between the inlet region and the outlet region; and, an electrical contact on at least one of the outer electrode and the inner electrode for applying a compensation voltage between the outer electrode and the inner electrode, and for applying an asymmetric waveform to the at least one of the outer electrode and the inner electrode such that, during use, some of the ions are selectively transmitted through the analyzer region between the inlet region and the outlet region along at least three different approximately shortest average ion flow paths that are other than parallel, one relative to another, along a substantial portion of a length thereof.