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Proceedings Paper

Thymol blue immobilized on tapered fibers as optical transducer for pH sensing
Author(s): Francesco Baldini; Leonardo Ciaccheri; Alida Falai; Anna Grazia Mignani; Jan Rayss; Grzegorz Sudolski
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Paper Abstract

The present work is concerned with the optical characterization of an evanescent wave sensor for pH detection. First, the interaction between the solution containing the acid-base indicator and the fiber core was investigated. Then, the acid-base indicator, thymol blue, was covalently immobilized on the core of a 200/380 micrometers fiber by means of a silylation process of the glass surface. The fiber core surface was modified along a section of 8 mm. A comparison was made using both bare and tapered fibers, with a tapering ratio (fiber diameter/waist diameter) of 2.3. An enhancement in sensitivity of a factor 6 was observed with tapered fibers in the 1/2.5 range, and a sensitivity of 0.05 pH units was attained.

Paper Details

Date Published: 23 February 1999
PDF: 6 pages
Proc. SPIE 3540, Chemical, Biochemical, and Environmental Fiber Sensors X, (23 February 1999); doi: 10.1117/12.339805
Show Author Affiliations
Francesco Baldini, IROE-CNR (Italy)
Leonardo Ciaccheri, IROE-CNR (Italy)
Alida Falai, IROE-CNR (Italy)
Anna Grazia Mignani, IROE-CNR (Italy)
Jan Rayss, Maria Curie-Sklodowska Univ. (Poland)
Grzegorz Sudolski, Maria Curie-Sklodowska Univ. (Poland)

Published in SPIE Proceedings Vol. 3540:
Chemical, Biochemical, and Environmental Fiber Sensors X
Robert A. Lieberman, Editor(s)

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