A new silver (I) ions optical sensor based on nanoporous thin films of sol–gel by rose bengal dye

Abstract In this work, a new optical sensor was fabricated based on the incorporation of rose bengal (RB) dye as ionophore into the nanopores of thin film prepared through the sol-gel technique which was suitable for the determination of silver (I) ions in aqueous solutions. The prepared thin films were composed of Tetraethoxysilane (TEOS), RB dye, methanol (MeOH), hydrochloric acid and Triton X-100. They were characterized by field emission scanning electron microscopy (FE-SEM) and atomic force microscope (AFM). The results confirmed the uniformity and low roughness of the prepared thin films. Average roughness of thin films was obtained to be about 2.5 nm. After sensing Ag ions, X-ray photoelectron spectroscopy (XPS) was performed to understand the mechanism of interaction of Ag ions with thin film. Leaching of this sensor was investigated and it was found that the proposed sensor is stable over the time without observing any change in its sensitivity. The proposed sensor revealed a maximum peak at 519 nm in its UV-vis spectra corresponding to silver (I) – RB complex with response time of 7 min at pH 7. HNO 3 was found to be the best regenerator reagent for this optical sensor. The constructed sensor displayed a working range for Ag (I) of 3.24 × 10 −6 –8.23 × 10 −7  mol L −1 with a detection limit of 9.8 × 10 −8  mol L −1 . The optode was tested in real water samples for the determination of Ag + ions with good selectivity.