# US 2014/0151545 A1 · Sensitive Ion Detection Device and Method for Analysis of Compounds as Vapors in Gases > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0151545 A1 - Document ID: US20140151545A1 - Status: Published application - Kind: A1 - Application number: 14/046,447 - Filed: 2013-10-04 - Published: 2014-06-05 - Earliest claimed: 2007-11-06 - Assignees: Arizona Board of Regents on Behalf of the University of Arizona - Applicants: The Arizona Board of Regents On Behalf of the University of Arizona - Inventors: M. Bonner DENTON; Roger P. SPERLINE - Web page: https://patentgrep.com/patent/US20140151545A1 ## CPC - G01N 27/622: Ion mobility spectrometry - H01J 49/02: Details - H01J 49/10: Ion sources; Ion guns - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) - H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H) ## Abstract 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. ## Claims ### Claim 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. ### Claim 2 (depends on 1) The ion mobility spectrometer of claim 1 wherein the flow of sample gas is not dried. ### Claim 3 (depends on 1) The ion mobility spectrometer of claim 1 wherein the direction of flow of the sample gas is transverse to the direction of electrophoresis. ### Claim 4 (depends on 3) The ion mobility spectrometer of claim 3 wherein the ionization volume of the ionization source is between 0.5 L and 2 L. ### Claim 5 (depends on 3) The ion mobility spectrometer of claim 3 further comprising an electric field gradient in the ionization region. ### Claim 6 (depends on 3) The ion mobility spectrometer of claim 3 wherein the ion source is one or more radioactive ionization sources. ### Claim 7 (depends on 3) The ion mobility spectrometer of claim 3 wherein the flow of sample gas is not dried. ### Claim 8 (depends on 1) The ion mobility spectrometer of claim 1 wherein the direction of flow of the sample gas is opposite in direction to the direction of electrophoresis. ### Claim 9 (depends on 8) The ion mobility spectrometer of claim 8 wherein the ionization volume of the ionization source is between 0.5 L and 2 L. ### Claim 10 (depends on 8) The ion mobility spectrometer of claim 8 further comprising an electric field gradient in the ionization region. ### Claim 11 (depends on 8) The ion mobility spectrometer of claim 8 wherein the ion source is a one or more radioactive ionization sources. ### Claim 12 (depends on 1) The ion mobility spectrometer of claim 1 wherein the ion source is a one or more radioactive ionization sources. ### Claim 13 (depends on 1) The ion mobility spectrometer of claim 1 wherein the ion source is a corona discharge or a photoionization source. ### Claim 14 A method for detecting analyte in a sample gas by ion mobility spectroscopy which comprises the steps of: (a) providing an ion mobility spectrometer (IMS) having a sample inlet for continuously receiving sample gas, 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 wherein primary ions charge transfer with analyte to generate secondary and tertiary ions; an ion shutter; a drift region having an electric field gradient providing a direction of electrophoresis of ions therein; and an ion detector; (b) continuously introducing sample gas to be assessed for the presence of analyte into the ionization region of the IMS, such that volumetric flow of sample gas is greater than 85 cm3/s and forming primary ions; (c) forming secondary and tertiary ions, including any analyte ions, in the reaction region; and (d) detecting the ions formed in the IMS, to thereby detect the presence of analyte. ### Claim 15 (depends on 14) The method of claim 14 wherein the flow of sample gas is not dried. ### Claim 16 (depends on 14) The method of claim 14 further comprising a step of preconcentration of the sample. ### Claim 17 (depends on 14) The method of claim 14 wherein the sample gas is ambient air. ### Claim 18 (depends on 14) The method of claim 14 wherein the volumetric flow rate of sample gas is 85-8,500 cm3/s. ### Claim 19 (depends on 14) The method of claim 14 wherein the direction of flow of the sample gas is transverse to the direction of electrophoresis. ### Claim 20 (depends on 14) The method of claim 14 wherein the direction of flow of the sample gas is opposite in direction to the direction of electrophoresis.