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Proceedings Paper

Fiber optic based chemical sensors for in-situ measurement of metals and aromatic organic compounds in seawater and soil systems
Author(s): Stephen H. Lieberman; Scott Inman; Gregory A. Theriault; Stafford S. Cooper; Philip G. Malone; Yasuhiro Shimizu; Paul W. Lurk
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Paper Abstract

Use of UV-visibletransmitting optical fibers for real-time, remote, in situfluorescencemeasurementsof chemical constituents in environmental samples is described. In order to improve the capability of fluorescence techniques for resoMng complex mixtures we have deVelOped a fiber optic-based system that uses a pulsed nrogen laser to induce fluorescence and a time-gated linear photodiode array coupled to a spectrograph for measuring resutting emisalon spectra This permfts rapid extraction of both spectral information and temporal data (fluorescence decay times). The performance of the system for monftoring aromatic hydrocarbons directly in seawater over a bare-ended" fiber optic cable is discussed. Techniques for extending the Capability to determination of metals and other non-fluorescing compounds are presented. A system in which a fluorogenic indicator molecule for metal ions is constantly renewed at the sensing end of the fiber is described that (1)exhibits very fast response times (1 second) and (2)eliminates problems of reversibility common with immobilized indicators. Presently, the pulsed-laser/photodiode fiber optic system is being adapted to a truck-mounted cone penetrometer system for characterizing the distribution of chemical contaminants at hazardous waste sites. The system can push a 35.7 mm diameter rod up to 50 m into the sI at a rate of approximately 2 cm/sec. The penetrometer probe tip will be equipped with sapphire viewing windows that permft one fiber to screen for aromatic orgarc compounds and a fluorogeruc indicator release system that can be used with a second fiber for trace metal screening.

Paper Details

Date Published: 1 August 1990
PDF: 10 pages
Proc. SPIE 1269, Environment and Pollution Measurement Sensors and Systems, (1 August 1990); doi: 10.1117/12.20353
Show Author Affiliations
Stephen H. Lieberman, Naval Ocean Systems Ctr. (United States)
Scott Inman, Naval Ocean Systems Ctr. (United States)
Gregory A. Theriault, Naval Ocean Systems Ctr. (United States)
Stafford S. Cooper, U.S. Army Engineer Waterways Experiment Station (United States)
Philip G. Malone, U.S. Army Engineer Waterways Experiment Station (United States)
Yasuhiro Shimizu, Nagasaki Univ. (Japan)
Paul W. Lurk, U.S. Army Toxic and Hazardous Materials Agency (United States)


Published in SPIE Proceedings Vol. 1269:
Environment and Pollution Measurement Sensors and Systems
Hans Ole Nielsen, Editor(s)

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