US 6,985,818 B1Granted

Air sampling method and sensor system for spectroscopic detection and identification of chemical and biological contaminants

AssigneeThe United States of America as represented by the Secretary of the Army

InventorAlan C. Samuels

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Abstract

A continuous monitoring method and system wherein a porous substrate or film is used. The air from the environment is drawn through a region of the porous substrate by a simple air pump and the substances in the air are deposited or chemically adsorbed onto the surface of the substrate. The region of the substrate where the environmental air is drawn through is continuously monitored by an optical or spectrometric method. The substrate is in the form of a tape supplied by a feed reel in a reel-to-reel cartridge and taken up by a take-up reel as found in a film cartridge or a magnetic tape cartridge. The cartridge can be replaceable. A variety of materials may be employed as the substrate with an adequate surface area to effect accumulation of solid, liquid, aerosol, or gas phase compounds. An optical interrogation system is engineered such that the surface of the tape at the point where air from the environment is drawn through the substrate becomes the interaction region between the source output and the sample. As material from the environment accumulates in this region, the interaction of the source with the material is monitored by a suitable detector and supporting circuitry.

Claims25

Dependent claims

A method for sampling and identifying atmospheric constituents, comprising:

(a) creating a library of known atmospheric constituents by drawing known atmospheric constituents through a sampling substrate and interrogating said constituents with an optical or spectrometric interrogation device to obtain a known spectral response thereof;
(b) collecting a baseline response of said sampling substrate by interrogating said substrate at a sampling area that is pristine;
(c) drawing unknown atmospheric constituents through said substrate at a sampling area thereon, said atmospheric constituents comprising one or more of chemical or biological substances in the form of a solid, liquid, aerosol and/or gas;
(d) interrogating said sampling area with optical or spectrometric interrogation devices to obtain an interrogation reading for said unknown constituents, wherein multiple interrogating devices are used concurrently to interrogate the same sample area to provide independent detection schemes that allow the system to self-confirm identification;
(e) comparing said interrogation reading of said unknown constituents with the library of known constituents and identifying said unknown constituents;
(f) advancing the sampling substrate so that a new sampling area of said substrate can be used and repeating steps c, d and e;
and
(g) demarcating the substrate so that the multiple sampling areas on said substrate can be archived and retrieved.

5 more elements

Dependencies are inferred from the claim text.