Electrically induced fluorescence Fe3+ sensing behavior of nanostructured Tiron doped polypyrrole.

Nanostructured polypyrrole (PPy) film doped with Tiron was electrodeposited from aqueous solution on the surface of transparent electrode and used for sensitive, selective and rapid electrically controlled fluorescence detection of Fe3+ in aqueous media. The fluorescence intensity of PPy-Tiron film decreases linearly in the presence of Fe3+ by applying negative potential over a concentration range from 5.0 × 10-8 to 1.0 × 10-6 mol L-1, with a relatively fast response time of less than 30 s at pH 7.4. The detection is not affected by the coexistence of other competitive metal ions such as Al3+, Ce3+, Tl3+, La3+, Bi3+, Cr2+, Mn2+, Fe2+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+, Hg2+, Pb2+, Na+, K+, Mg2+, Ca2+, Sr2+ and Ba2+. The proposed electro-fluorescence sensor has a potential application to the determination of Fe3+ in environmental and biological systems. The fluorescent thin film sensor was also used as a novel probe for Fe3+/Fe2+ speciation in aqueous solution.