Allied Corporation

Alliedsignal Inc.

Environmental Technologies Group, Inc.

Kishore N Vora

Donald N Campbell

Glenn E Spangler

Robert C Davis, Jr

Julio A Reategui

John P Carrico, Jr

Charles E Martin

An ion mobility spectrometer, ionization detector and mass spectrometer is described having a reaction region, and a region for introducing a sample gas, liquid or solid samples into the reaction region and an electrolyte in the reaction region of an alkali salt heated to a predetermined temperature, such as room temperature to 1000.degree. C., to provide a chemical reaction between the alkali atoms, cations or complement anions with the sample to provide product ions. The invention provides a non-radioactive ionization source for ionization of a broad class of compounds.

Selective ionization of gas constituents using electrolytic reactions

An ion mobility spectrometer, ionization detector and mass spectrometer is described having a reaction region, and means for introducing a sample gas, liquid or solid samples into the reaction region and an electrolyte in the reaction region of an alkali salt heated to a predetermined temperature, such as room temperature to 1000.degree. C., to provide a chemical reaction between the alkali atoms, cations or complement anions with the sample to provide product ions. The invention provides a non-radioactive ionization source and provides a means for ionization of a broad class of compounds.

An ion mobility spectrometer is described for detecting gas constituents in an ambient air incorporating a cylindrical tube containing a reaction region, a shutter assembly and a drift region therein, the cylindrical tube fits within a housing having a chamber or space between the cylindrical tube and the housing for heating drift gas prior to entry into the drift region. Further, the cylindrical tube may have interior annular ledges to facilitate positioning of the shutter assembly and an aperture grid. The invention overcomes the problem of controlling the temperature of the drift gas prior to entry into the drift region to enhance the uniformity of ion drift mobility times and the problem of a mechanical assembly which is difficult to dissemble.

Ion mobility spectrometer

A gas tight cell receives an unmetered stream of sample gas. The cell is divided into a reaction chamber, as drift chamber and an ion collector chamber by transverse shutter grids normally carrying an ion repellent charge. The inlet of a chromatograph analytical column is connected to the outlet of the cell ion collector chamber. Inert gas admitted to the ion collector chamber is divided into a drift gas stream and into an oppositely directed carrier gas stream. The drift gas flows from the collector chamber through the drift chamber and out the reaction chamber. The carrier gas flows from the collector chamber through a deionizer into the chromatograph column. An electrostatic field urges sample gas ions from the reaction chamber toward the ion collection chamber. The ions are blocked from entering or exiting from the intervening drift chamber by the charge on the shutter grids. At selected times the repellent charges are removed from the shutter grids to allow a group of sample gas ions to traverse the drift chamber and enter the ion collection chamber. Such ions become entrained in the carrier gas stream and are transported thereby through the deionizer into the chromatograph column. The waveform of the current induced in the deionizer by sample gas ions passing therethrough provides information on the time, volume and shape of the gas sample admitted to the chromatograph column.

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Annandale, VA, United States of America

Kishore N Vora