Intrinsic fiber optic absorption sensors for the detection of volatile organic compounds
- Lawrence Livermore National Laboratory, CA (United States)
Extensive contamination of ground water from organic solvents has placed a large emphasis on the development of instruments for remote in-situ sensing. Fiber optic chemical sensors (FOCSs) have made a great deal of progress in this area. The authors have investigated two intrinsic FOCSs for the detection of volatile organic compounds. One is based on evanescent wave absorption and the other is a direct absorption core-based sensor. Both sensors make use of silicone polymers as selective membranes to extract the volatile analyte from the aqueous solution for analysis in the NIR. The rate limiting step for analyte diffusion into the membrane has been determined to be diffusion through the Nernstian boundary. With each sensor, the times required to reach an equilibrium response are on the order of 30 minutes for 20 ppm aqueous solution of trichloroethylene. Headspace measurements are much faster and reach equilibrium in 3-5 minutes. A comparison of the two sensors, detection limits, diffusion rates and effects of temperature will be discussed.
- OSTI ID:
- 191754
- Report Number(s):
- CONF-941098-; TRN: 95:006733-0110
- Resource Relation:
- Conference: FACSS XXI: 21st annual conference of the Federation of Analytical Chemistry and Spectroscopy Societies (FACSS), St. Louis, MO (United States), 2-7 Oct 1994; Other Information: PBD: 1994; Related Information: Is Part Of 21st annual conference of the Federation of Analytical Chemistry and Spectroscopy Societies; PB: 257 p.
- Country of Publication:
- United States
- Language:
- English
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