Laser-based detection of nitro-containing compounds

Details Laser-based detection of nitro-containing compounds Laser-based detection of nitro-containing compounds

1993-06-11

1994-11-15

Housel, James C.

Chemistry: analytical and immunological testing

Nitrogen containing

436110, 436116, 436153, 436172, 73 35, 2504611, G01N 3322

Patent

active

053647955

ABSTRACT:
An apparatus and method for the sensitive detection of atmospheric and/or surface absorbed nitrocompounds has been developed. The apparatus and method may be employed to detect the presence or absence of propellants, explosives, and nitropollutants. The unique feature herein is that the apparatus and method employ one laser operating at or near 226 nm. The laser photofragments the target molecule and facilitates the detection of the characteristic NO fragment, by resonance-enhanced multiphoton ionization (REMPI) and/or laser-induced-fluorescence (LIF) via its A.sup.2 .SIGMA..sup.+ -X.sup.2 II.sub.i transitions. The analytical utility of this apparatus and method has been demonstrated on numerous compounds, such as, DMNA, nitromethane, nitro-benzene, TNT, and RDX. With the present system, a limit of detection of 8 and 24 ppb is obtained for RDX and TNT, respectively, using only 100 micro-Joules per pulse of laser energy. Limits in the sub parts-per-trillion are projected using higher laser energies and improved system design.

REFERENCES:
patent: 3826920 (1974-07-01), Woodroffe et al.
patent: 4066904 (1978-01-01), Bertaux et al.
patent: 4315753 (1982-02-01), Bruckenstein et al.
patent: 4775633 (1988-10-01), Rounbehler
patent: 5094815 (1992-03-01), Conboy et al.
patent: 5123274 (1992-06-01), Carroll et al.
Asscher et al. "Two-Photon Excitation as a Monitoring Technique for Photosociation Dynamics: (F.sub.3 NO.sub.-7 CF.sub.3+ NO(v,J)", J. Chem Phys 72(1) 1980, pp. 768-769.
Rodgers et al. "Photofragmentation Laser Induced Fluorescence: A New Method for Detecting Atmospheric Trace Gases" Applied Optics, v. 19 No. 21, 1980, pp. 3597-3605.
Mukhtar et al. "Photodissociation of Positive Molecular Ions of Nitrobenzene" Organic Mass Spectrometry v. 15, No. 1 1980 pp. 51-52.
Rockney et al. "Resonant Multiphoton Ionization Detection of the NO.sub.2 Fragment from Multiphoton Dissocation of CH.sub.3 NO.sub.2 " Chem. Phys Letters v 79, No. 1, 1981 pp. 15-18.
Bunn et al. "Photodissociation of the Energy Selected Nitrobenzene Ion" J. Chem. Phys. 84(3) 1986 pp. 1424-1431.
Nobel et al. "Photodissociation of Jet Cooled (CH.sub.3).sub.3 CNO: Temporal Separation of Radiation Less Transitions and Unimolecular Reactions" J. Chem Phys. 84(6) 1986. pp. 3573-3574.

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