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Proceedings Paper

Renewable Reagent Fiber Optic Based Ammonia Sensor
Author(s): Richard J. Berman; Lloyd W. Burgess
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Paper Abstract

Many fiber optic based chemical sensors have been described which rely on a reagent chemistry fixed at the fiber endface to provide analyte specificity. In such systems, problems involving probe-to-probe reproducibility, reagent photolability and reagent leaching are frequently encountered. As a result, calibration and standardization of these sensors becomes difficult or impossible and thus inhibits their application for long term in situ chemical monitoring. Many of these problems can be addressed and several additional advantages gained by continuously renewing the reagent chemistry. To illustrate this concept, a fiber optic ammonia sensor is described in which the reagent is delivered under direct control to a sensing volume of approximately 400 nanoliters located at the probe tip. Using an acid-base indicator (bromothymol blue) as the reagent, the sample ammonia concentrations are related to modulations in light intensity with a lower limit of detection of 10 ppb. The sensor performance was studied with respect to reagent pH, concentration and reagent delivery rate. Compared with previous fiber optic ammonia sensors, the ability to reproducibly renew the reagent has resulted in improvements with respect to response and return times, probe-to-probe reproducibility, probe lifetime and flexibility of use.

Paper Details

Date Published: 13 February 1990
PDF: 10 pages
Proc. SPIE 1172, Chemical, Biochemical, and Environmental Fiber Sensors, (13 February 1990); doi: 10.1117/12.963190
Show Author Affiliations
Richard J. Berman, University of Washington (United States)
Lloyd W. Burgess, University of Washington (United States)

Published in SPIE Proceedings Vol. 1172:
Chemical, Biochemical, and Environmental Fiber Sensors
Robert A. Lieberman; Marek T. Wlodarczyk, Editor(s)

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