Fabrication and characterization of U-shaped fiber-optic pH probes

Abstract Fabrication and characterization of U-shaped fiber optic pH probes utilizing evanescent field absorption spectroscopy and dye doped sol–gel immobilization technology are presented. The U-shaped probe is used to increase the evanescent field in the film and hence its interaction with the dyes present in the film. The influences of bending radius of the probe and the numerical aperture of the fiber on the sensitivity of the sensor are studied. It has been shown that, for a given pH, as the bending radius of the U-shaped probe decreases the sensitivity of the sensor increases. Further, for a given bending radius and the fiber core diameter, increase in the numerical aperture of the fiber increases the sensitivity of the pH sensor. The response time of the sensor reported in the present study is approximately 15 s.

[1]  Joseph R. Lakowicz,et al.  Fiber Optic pH Sensor Based on Phase Fluorescence Lifetimes. , 1993, Analytical chemistry.

[2]  D. Avnir,et al.  Simple Absorption Optical Fiber pH Sensor Based on Doped Sol−Gel Cladding Material , 1997 .

[3]  Banshi D. Gupta,et al.  Evanescent wave absorption based fiber optic pH sensor prepared by dye doped sol-gel immobilization technique , 1997 .

[4]  Banshi D. Gupta,et al.  A long-range fiber optic pH sensor prepared by dye doped sol-gel immobilization technique , 1998 .

[5]  Banshi D. Gupta,et al.  Fibre-optic evanescent field absorption sensor based on a U-shaped probe , 1996 .

[6]  George H. Sigel,et al.  Fibre optic pH sensors prepared by sol-gel immobilisation technique , 1991 .

[7]  K. Cammann,et al.  A fibre-optical sensor for the determination of sodium with a reversible response , 1992 .

[8]  E. Saaski,et al.  Development of a medical fiber-optic pH sensor based on optical absorption , 1992, IEEE Transactions on Biomedical Engineering.

[9]  Banshi D. Gupta,et al.  Fiber optic evanescent field absorption sensor based on a tapered probe: effect of fiber parameters on the response curve , 1999, Other Conferences.

[10]  L. Bachas,et al.  Fluorocarbon-based immobilization of a fluoroionophore for preparation of fiber optic sensors , 1993 .

[11]  S R Goldstein,et al.  Fiber optic pH probe for physiological use. , 1980, Analytical chemistry.

[12]  Otto S. Wolfbeis,et al.  LED-compatible fluorosensor for measurement of near-neutral pH values , 1992 .

[13]  Sunil K. Khijwania,et al.  Fiber optic evanescent field absorption sensor: Effect of fiber parameters and geometry of the probe , 1999 .

[14]  Frank Kvasnik,et al.  Distributed Chemical Sensing Utilising Evanescent Wave Interactions , 1990, Other Conferences.

[15]  Jennifer W. Parker,et al.  Fiber-optic sensors for pH and carbon dioxide using a self-referencing dye , 1993 .

[16]  Sheila A. Grant,et al.  A sol–gel based fiber optic sensor for local blood pH measurements , 1997 .

[17]  Brendan C. O'Kelly,et al.  Optical waveguide sensor using evanescent wave excitation of fluorescent dye in sol-gel glass , 1991 .