Chitosan coated fluorescent mesoporous silica for the sensitive and selective detection of H₂O₂

A novel turn-on fluorescent sensor for hydrogen peroxide (H₂O₂) was prepared from chitosan (CS) coating mesoporous silica nanoparticles (MSNs) loaded with 1-(4-Aminophenyl)-1,2,2-triphenylethene (TPE-NH₂) and silver nanoparticles (AgNCs). The surface of MSNs was coated by CS as the gatekeeper and the template for loading of AgNCs. Because of the surface plasmon-enhanced energy transfer (SPEET), AgNCs effectively quenched the fluorescence emission of nanoparticles. In the presence of H₂O₂, AgNCs can be oxidized to Ag⁺, resulting in the recovery of fluorescence. This fluorescent sensor was characterized with respect to its chemical composition, morphological features and optical properties by means of FTIR, XRD, TGA, SEM, TEM, XPS, UV-Vis and fluorescence spectroscopy. The MSN/TPE-CS@Ag nanoparticles showed good sensitivity and selectivity for H₂O₂ even with various interfering ions and agents. Under optimized conditions, the detection limit for H₂O₂ was 0.64 μM in the rage of 1-300 μM. The feasibility of the practical application of this probe was confirmed by accurate quantitative of H₂O₂ in practical samples.