DRIFT TUBE ION MOBILITY SPECTROMETER FOR AEROSOL MEASUREMENT

摘要

A drift tube ion mobility spectrometry sample introduction scheme allows introduction of a sample packet at ground voltages. The sample packet of ionized particles is captured by subjecting particles within a defined region to an electric field at an elevated voltage. The ionized particles in the captured packet then migrate through the drift tube down the voltage gradient according to their electrical mobility. The particles are directed to a high sensitivity detector, such as a condensation particle counter (CPC), for detection.

主权项

1. A method comprising:
introducing a sample aerosol into a drift tube of an ion mobility spectrometer; introducing a carrier gas into the drift tube of the ion mobility spectrometer such that at least a portion of the carrier gas flows through the drift tube in a direction generally opposing migration of ionized particles through the drift tube,
wherein the sample aerosol and carrier gas are introduced into the drift tube such that the sample aerosol circulates within a portion of the drift tube, andwherein an applied electrostatic separation field blocks migration of ionized particles in the sample aerosol into a separation region of the drift tube; and applying a capturing electric field to the drift tube to increase the electrical potential of ionized particles within at least a portion of the sample circulation to a potential greater than that of the applied electrostatic separation field to allow the ionized particles at the increased potential to migrate in the drift tube down a gradient of the applied separation field against the flow of the carrier gas to separate according to their ion mobility.