Boehmite supported pyrene polyamine systems as probes for iodide recognition

New organic-inorganic fluorescent probes made by attaching the tripodal polyamine (tris(2-aminoethyl))amine (tren), propylamine, or diethylenetriamine functionalized with pyrene as a fluorophore to an γ-aluminum oxohydroxide matrix have been prepared and studied both in solution and supported on the surface of boehmite nanoparticles. Both kinds of systems have been revealed as sensitive and selective fluorescence turn-off chemosensors for iodide in aqueous solution with an estimated detection limit that reaches 36 ppb. The recognition characteristics and photophysical properties of these molecules are essentially preserved when they are grafted to the surface of the particles. Since the nanoparticles are stable over a wide pH window and they can be easily recovered by centrifugation and filtration, these systems present the advantage that can be repeatedly used for the detection of iodide.