Preparation of lucigenin-doped silica nanoparticles and their application in fiber optic chloride ion sensor

Abstract

A novel fiber optic sensor was developed to detect chloride ion by means of a cellulose acetate (CA) sensitive film, in which the lucigenin-doped silica nanoparticles were synthesized by the reverse microemulsion method and immobilized into sensitive membrane via physical embedding and. The morphology, structure and fluorescence performance of the lucigenin-doped silica nanocomposite particles were characterized by scanning electron microscope (SEM), Brunauer-Emmett-Teller (BET) nitrogen adsorption-desorption isotherms, Fourier transforming infrared (FT-IR), Ultraviolet absorption spectrometer and Fluorescence spectrometer, respectively. The results show that the lucigenin-doped silica nanocomposite particles still had excellent fluorescence performance and high sensitivity for chloride detection, even fluorescence stability was improved compared with single lucigenin. Based on the principle of fluorescence quenching, that is the fluorescence intensity of lucigenin-doped silica nanoparticles will decrease with increasing of the chloride ion concentrations, the chloride concentrations were detected by the fiber optic sensor, in which the end face of optic fiber was coated with the CA sensitive film. The relationship between the intensity of lucigenin-doped silica nanoparticles and the concentrations of chloride ion followed the Stern–Volmer equation, and a linear relationship formula of I0I=1.623+49.845[Cl−](R2=0.995) was obtained with the concentration range from 0.02 M to 0.06 M.