Sensitive Ion Detection Device and Method for Analysis of Compounds as Vapors in Gases

摘要

An ion mobility spectrometer (IMS) for the detection of trace gaseous molecular compounds dissolved or suspended in a carrier gas, particularly in ambient air, without preconcentration or the trapping of analyte particles. The IMS of the invention comprises an ionization volume of greater than 5 cm3 and preferably greater than 100 cm3. The larger size ionizers of this invention enable analysis of trace (<1 ppb) of sample compounds in the gas phase. To facilitate efficient ion motion through the large volume ionization and reaction regions of the IMS, an electric field gradient can be provided in the ionization region or in both the ionization and reaction regions. The systems can be implemented with radioactive ionization sources, corona discharge ion sources or ions can be formed by photoionization. In specific embodiments, particularly when the sample gas is ambient air, the sample gas is heater prior to entry into the instrument, the instrument is run at temperatures above ambient, and the instrument can be heated by contact with heated sample gas exiting the instrument.

主权项

1. An ion mobility spectrometer for detection of analyte which comprises:
a sample inlet for continuously receiving a flow of sample gas wherein the volumetric flow of sample gas is greater than 85 cm3/s; an ionization region for formation of primary ions which comprises an ion source, wherein the ionization volume of the ionization source is greater than 5 cm3; a reaction region for receiving the flow of sample gas containing primary ions, wherein primary ions can charge transfer to generate secondary and tertiary ions including analyte ions; an ion shutter; a drift region having an electric field gradient; and an ion detector; wherein the ion shutter gates the entrance of ions into the drift region, the ions in the drift region drift in the electric field gradient in the direction of electrophoresis to be detected at the ion detector, thereby allowing detection of analyte.