Silica-supported indole derived fluorometric chemosensor for the selective detection of Ag+ ions in aqueous solution

Abstract

A novel organic-inorganic hybrid nanomaterial-based fluorescent chemosensor was synthesized by functionalizing rice husk-derived nanosilica with 3-(aminopropyl)triethoxysilane (APTES) and then grafting it with para-aminobenzoic acid, benzaldehyde, and indole organic moieties, respectively, to detect Ag+ ions in the aqueous medium. Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), fluorescence spectroscopic techniques, and thermogravimetric analysis (TGA) were used to characterize the synthesized material. The synthesized ligand showed highly selective and sensitive fluorescence-enhanced, "Turn-ON" chemosensor activity towards Ag+ ions at an excitation wavelength of 355 nm, with observable variations in fluorescence intensity compared to other metal ions. The detection limit for Ag+ was 1.94 × 10−4 M, and the limit of quantification was calculated as 6.49 × 10−4 M. These findings suggest that the silica-supported indole derivative (Indole-APTES@nanosilica) can be utilized as a sensitive and selective, Turn-ON fluorometric chemosensor for detecting Ag+ ions.