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28 March 1994 Real-time detection of hazardous materials in air
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Proceedings Volume 2092, Substance Detection Systems; (1994)
Event: Substance Identification Technologies, 1993, Innsbruck, Austria
A new detection system has been developed for real-time analysis of organic compounds in ambient air. It is based on multiphoton ionization by an unfocused laser beam in a single parallel-plate device. Thus, the ionization volume can be relatively large. The amount of laser created ions is determined quantitatively from the induced total voltage drop between the biased plates (Q equals (Delta) V(DOT)C). Mass information is obtained from computer analysis of the time-dependent signal. When a KrF laser (5 ev) is used, most of the organic compounds can be ionized in a two-photon process, but none of the standard components of atmospheric air are ionized by this process. Therefore, this instrument may be developed as a `sniffer' for organic materials. The method has been applied for benzene analysis in air. The detection limit is about 10 ppb. With a simple preconcentration technique the detection limit can be decreased to the sub-ppb range. Simple binary mixtures are also resolved.
© (1994) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Israel Schechter, Hartmut Schroeder, and Karl Ludwig Kompa "Real-time detection of hazardous materials in air", Proc. SPIE 2092, Substance Detection Systems, (28 March 1994);

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