An Optical Fiber ${\rm H}_{2}{\rm O}_{2}$-Sensing Probe Using a Titanium(IV) Oxyacetylacetonate Immobilized Nafion Coating on an Bent Optical Fiber Probe

Abstract

An optical fiber sensor technique has been developed for monitoring trace H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> in aqueous solutions. A titanium(IV) oxyacetylacetonate doped Nafion coating on the surface of a bent optical fiber probe was used as a transducer. Trace H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> in an aqueous solution diffused into the polymer coating reacts with the sensing agent. The resulted product absorbs light with peak absorption wavelength at 360 nm, which is detected by using optical fiber evanescent wave absorption spectrometry. This sensor reversibly responses to trace H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> in water, and has a detection limit (3σ) of 7.4 <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">*</sub> 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-8</sup> mole H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> /L. This fiber-optic sensor is immune of interferences from electromagnetic field which makes it useful in proton exchange membrane fuel cell researches.