Patent ID: 7858927
Filing Date: 2010-12-28
Classification: G01N,H01J

Abstract:
1. A method of providing a Differential Mobility Analyzer (DMA) that can operate in several modes of operation, wherein the method comprises: providing a chamber having a first plate with first and second inlet apertures and a second plate with an exit aperture, the second plate being located relative to the first plate to define a DMA drift region; providing the first inlet aperture at a position that is generally opposite to and aligned with the exit aperture and a second inlet aperture at a position that is offset with respect to the exit aperture; providing a laminar gas flow element that is operable to create a sheath gas flow in the DMA drift region when provided with a gas flow during use; and configuring the DMA to receive voltages, wherein during use, the voltages are applied to the DMA to generate an electric field between the first and second plates, wherein, during use, in a first mode of operation sample ions provided to the second inlet aperture are separated based on mobility to provide a portion of the sample ions to the exit aperture, and in a second mode of operation another portion of sample ions provided to the first inlet aperture are provided to the exit aperture without mobility separation.