Carbon dot doped silica nanoparticles as fluorescent probe for determination of bromate in drinking water samples

A simple and effective strategy for designing a fluorescent probe for bromate was described in this work. Organosilane modified carbon dots were prepared by pyrolysis of citric acid in N-(β-aminoethyl)-γ-aminopropyl methyldimethoxysilane solvent at 230 °C and further doped onto silica nanoparticles by a silylation reaction. The fluorescence of carbon dot doped silica nanoparticles was quenched by bromate in acidic medium. By utilizing this property, the nanoparticle could be used as a sensor to detect bromate. The parameters affecting the performance of the sensor probe such as types of acid medium, acid concentration, reaction temperature, and time were investigated and optimized. The detection limit of the sensor was found to be 1.1 ng mL−1, with a linear range from 8 to 400 ng mL−1 and relative standard deviation of 2.0% (150 ng mL−1, n = 9). The method was successfully applied to the determination of bromate in drinking water samples, and the recoveries were in the range of 96.3%–103.7%.