The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 17, 1998
Filed:
Sep. 30, 1994
Rosario C Sausa, Bel Air, MD (US);
Josef B Simeonsson, Iowa City, IA (US);
George W Lemire, Draper, UT (US);
The United States of America as represented by the Secretary of the Army, Washington, DC (US);
Abstract
A method for the ultra-sensitive detection of atmospheric and surface adsorbed nitrocompounds such as propellants, explosives, and nitro-pollutants employs an excimer (ArF) laser operating at or near 193 nm to photofragment the target molecule and facilitate the detection of the characteristic NO fragment, formed from the dissociation of NO.sub.2, by resonance-enhanced multiphoton ionization (REMPI) and/or laser induced fluorescence (LIF) via its A-X, B-X, C-X, and/or D-X electronic transitions. In addition to NO, the detection of other fragments, such as C, CH, C.sub.2, NH and OH, by their ionization and/or prompt emission resulting from 193 nm excitation enhances the analyte identification. The analytical utility of this apparatus and method has been demonstrated on a number of compounds including dimethylnitramine (DMNA), nitromethane, nitrobenzene, orthonitrotoluene, para-nitrotoluene and trinitrotoluene (TNT). With the present system, limits of detection in the tens to hundreds of parts-per-billion (ppb) range have been achieved in the gas phase for all of these compounds, using only 1 mJ of laser energy at 193 nm.