Patent ID: 6621077
Filing Date: 2003-09-16
Classification: G01N

Abstract:
An apparatus for selectively transmitting ions and trapping said ions within a defined 3-dimensional space, comprising:a) at least one ionization source for producing ions; b) a high field asymmetric waveform ion mobility spectrometer, comprising an analyzer region defined by a space between at least first and second spaced apart electrodes for connection, in use, to an electrical controller capable of supplying an asymmetric waveform voltage and a direct-current compensation voltage for selectively transmitting a selected ion type in said analyzer region between said electrodes at a given combination of asymmetric waveform voltage and compensation voltage, said analyzer region having a gas inlet and a gas outlet for providing, in use, a flow of gas through said analyzer region, said analyzer region further having an ion inlet for introducing a flow of ions produced by said ionization source into said analyzer region; and c) a curved surface terminus provided on at least one of said electrodes, said terminus being a part of said one of said electrodes which part is closest to said gas outlet, said defined 3-dimensional space being located near said terminus, whereby, in use, said asymmetric waveform voltage, compensation voltage and gas flow are adjustable, so as to trap said transmitted ions within said 3-dimensional space.