Patent ID: 6504149
Filing Date: 2003-01-07
Classification: B01D,G01N,H01J

Abstract:
An apparatus for selectively transmitting and determining the mass to charge ratio of ions, comprising:a) at least one ionization source for producing ions; b) a high field asymmetric waveform ion mobility spectrometer, comprising: i) an analyzer region including a space between first and second parallel surface regions of first and second spaced apart electrodes, respectively, said analyzer region having a gas inlet at a first end and a gas inlet at a second end for providing a flow of gas through said analyzer region, an ion inlet for introducing a flow of ions produced by said ionization source into said analyzer region, and an ion out at the second end for allowing extraction of ions from said analyzer region; ii) an electrical controller conectable to said electrodes and capable of applying an asymmetric waveform voltage and a direct-current compensation voltage, to selectively transmit a type of ion in said analyzer region between said parallel surface regions of said electrodes, at a given combination of asymmetric waveform voltage and compensation voltage; and iii) an ion diverting region at the second end of the analyzer region for receiving the selectively transmitted ions moving along the ion flow path, and for concentrating and directing the selectively transmitted ions toward said ion outlet of the analyzer region; and, c) a mass spectrometer having a sampler orifice being positioned proximate to said ion outlet to receive said selectively transmitted ions for analysis within said mass spectrometer, wherein absent the ion diverting region, a substantially smaller fraction of the selectively transmitted ions are sampled by the sampler orifice.