A non-enzyme hydrogen peroxide sensor based on core/shell silica nanoparticles using synchronous fluorescence spectroscopy

In our previous study, we have prepared aminated fluorescent silica nanoparticles doped with fluorescein isothiocyanate (FITC) (FSNPs) for the sensing of γ-globulin. Compared with conventional organic dyes, FSNPs show superiorities such as excellent photostability, good water solubility, and biocompatibility, which are in favor of improving the stability and sensitivity of sensors. To extend the application of FSNPs, a convenient and effective method for non-enzyme fluorescent sensor of hydrogen peroxide (H₂O₂) is introduced based on the synchronous fluorescence technique. The sensor includes two-step reactions, typical redox reaction between KI and H₂O₂ and iodination reaction between I₂ produced by the first step reaction and FITC doped in the network of silica nanoparticles, which induce the fluorescence quenching of FSNPs. The results show that the fluorescence signal of FSNPs linearly decreases with the trace amounts of hydrogen peroxide added in the range 5–80 μM with a detection limit of 0.8 μM under the optimal experimental conditions. The method is simple and sensitive and can be applied to the determination of trace amounts of H₂O₂. Good recovery data were obtained for the assay of H₂O₂ in river water by standard addition method with high accuracy and reliability.