A GBI@PPyNWs-based prototype of reusable fluorescence sensor for the detection of Fe3+ in aqueous solution

Abstract

Polypyrrole nanowires (PPyNWs) anchored with 2-guanidinobenzimidazole (GBI) molecules (denoted as GBI@PPyNWs) have been achieved via porous anodic aluminum oxide (AAO) template-assisted approach, and used for sensitive and selective rapid fluorescence detection of Fe³⁺ based on the formation of coordination compound between GBI and Fe³⁺. The fluorescence intensity of the GBI@PPyNWs increases linearly with [Fe³⁺] ranging from 10⁻⁵ to 1.4 × 10⁻⁴ M in water solution, while in ethanol/water solution it linearly decreases with [Fe³⁺] ranging from 2 × 10⁻⁶ to 3.8 × 10⁻⁵ M, both with good selectivity. The GBI@PPyNWs were used to detect Fe³⁺ in blood serum solution successfully. Moreover, the GBI@PPyNWs are reusable. Our new conceptual design, using the assembly of two biocompatible materials of PPy and GBI, for the detection of Fe³⁺ in aqueous solution, has potential in biological detection and may open a door to the design of effective fluorescence probes for other metal ions.