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Proceedings Paper

Use Of Time-Resolved Spectral Fluorometry For Improving Specificity Of Fiber Optic-Based Chemical Sensors
Author(s): S. H. Lieberman; S. M. Inman; G. A. Theriault
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Paper Abstract

The use of time-resolved fluorescence measurements is described as a means of improving the specificity of fiber optic sensors for analysis of environmental samples. Excitation of the sample is accomplished using a pulsed-nitrogen laser. The resulting fluorescence signal is coupled into the fiber and dispersed with a spectrograph over an intensified linear photodiode array. Fluorescence decay spectra are measured by time-gating the photodiode array and incrementing the time delay for successive laser pulses. A sensor system for trace transition metals is described which employs an organic indicator molecule, p-Tosy1-8- aminoquinoline (PTAQ), that forms fluorescent complexes with Zn and Cd. Data is presented in which differences'in fluorescent decay times of the Zn and Cd complex of PTAQ are used to deconvolve fluorescent signals from solutions containing micro-molar to nano-molar concentrations of the two metals. Time-resolved fluorescence measurements over fiber-optic cables have also been used to discriminate polycyclic aromatic hydrocarbons (PAHs) that cannot be resolved based on their fluorescence emission spectra. Comparison of decay times determined for selected PAHs in seawater with decay times in deoxygenated solvents suggest that it is feasible to use time-resolved fluorescence to enhance specificity of measurements in natural samples.

Paper Details

Date Published: 13 February 1990
PDF: 5 pages
Proc. SPIE 1172, Chemical, Biochemical, and Environmental Fiber Sensors, (13 February 1990); doi: 10.1117/12.963177
Show Author Affiliations
S. H. Lieberman, Naval Ocean Systems Center (United States)
S. M. Inman, Naval Ocean Systems Center (United States)
G. A. Theriault, Naval Ocean Systems Center (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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