Facile fabrication of fluorescent poly(5-cyanoindole) thin film sensor via electropolymerization for detection of Fe3+ in aqueous solution.

A fluorescent conjugated polymer thin film sensor via the electropolymerization for fluorescent detection of Fe 3+ in aqueous solution was successfully fabricated using a poly(5-cyanoindole) (P5CI), which was electrochemically prepared in the mixed electrolyte of boron trifluoride diethyl etherate, diethyl ether and tetrabutylammonium tetrafluoroborate on ITO electrodes by successive cyclic voltammetry. The thickness of the electropolymerized P5CI thin film could be precisely controlled by optimizing scan cycles and scan rates. The as-obtained fluorescent P5CI thin film sensor could effectively recognize Fe 3+ with outstanding sensitivity, selectivity, reversibility and reproducibility over other commonly coexistent metal ions and anions, and realize the quantitative determination of Fe 3+ in a linear range of 0.2 μM–0.5 mM with a detection limit of 0.897 ppb. The reversibility and reproducibility of P5CI thin film sensor were assessed. Satisfactory results indicated that fluorescent conjugated polymers via the electropolymerization provided a promising candidate for fluorescent thin film sensor. [ABSTRACT FROM AUTHOR]