A Rapid Vapor Concentrator and Detection System for Nitroaromatics


Dubey, A. C. and Harvey, J. F. and Thomas, Broach J. and George, V.


An automated, rapid-cycling vapor concentrator and sensor was designed and evaluated for detection of nitroaromatic compounds. The concentrator consists of an inert deactivated fused silica capillary loop. The temperature of the loop was manipulated through contact with a cold plate or a hot plate. Plates were maintained at pre-selected temperatures with a thermoelectric cooler and a cartridge heater. The low thermal mass of the loop permitted rapid trapping and desorption cycles. The chemical inertness of the fused silica tubing not only led to efficient transfer of nitroaromatics from the air stream to the detection system but also minimized cross contamination between samples. The detection system consisted of a tandem arrangement of electron attachment detectors and an electron attachment reactor. These devices were operated with compact custom electronics. The use of the electron attachment reactor and thermoelectric cooler permitted enhanced selectivity. The device was evaluated for rapid determination of nitroaromatic from air streams at trace concentrations. Detection limits down to sub parts per billion (ppb) were obtained.



Keywords and Phrases

Aromatic Hydrocarbons; Cooling; Desorption; Electric Reactors; Fused Silica; Sensors; Thermoelectricity; Vapors; Vapor Concentrators; Mines; Automated; Detection; Nitroaromatic; Rapid; Sampling

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Document Type

Article - Conference proceedings

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© 2001 SPIE -- The International Society for Optical Engineering, All rights reserved.

Publication Date

01 Oct 2001