A quantitative colorimetric assay of H₂O₂ and glucose using silver nanoparticles induced by H₂O₂ and UV

A simple spectrophotometric assay of H₂O₂ and glucose using Ag nanoparticles has been carried out. Relying on the synergistic effect of H₂O₂ reduction and ultraviolet (UV) irradiation, Ag nanoparticles with enhanced absorption signals were synthesized. H ₂O₂ served as a reducing agent in the Ag nanoparticles formation in which Ag⁺ was reduced to Ag⁰ by O ₂^- generated via the decomposition of H₂O ₂ in alkaline media. On the other hand, photoreduction of Ag ⁺ to Ag⁰ under UV irradiations also contributed to the nanoparticles formation. The synthesized nanoparticles were characterized by TEM, XPS, and XRD. The proposed method could determine H₂O ₂ with concentrations ranging from 5.0 × 10^-7 to 6.0 × 10^-5 mol/L. The detection limit was estimated to be 2.0 × 10^-7 mol/L. Since the conversion of glucose to gluconic acid catalyzed by glucose oxidase was companied with the formation of H ₂O₂, the sensing protocol has been successfully utilized for the determination of glucose in human blood samples. The results were in good agreement with those determined by a local hospital. This colorimetric sensor thus holds great promises in clinical applications.