Nanosilver resonance scattering spectral method for determination of hydroxyl radical and its application

Silver nanoparticles were prepared under a microwave high-pressure condition using citric acid sodium as a reducer while the excess citrate was removed under high speed centrifugation. There is a resonance scattering (RS) peak at 470 nm for silver nanoparticles. In a pH 4.0 HAc-NaAc buffer solution, hydroxyl radicals from the Fenton reaction can oxidize silver nanoparticles to Ag+, resulting in the RS intensity decreasing. The decreased RS intensity at 470 nm (Delta/ (470 nm)) is linear with respect to the concentration of H2O2 (C) in the range of 0.27-7.56 mu mol/L with a detection limit of 0.23 mu mol/L. Its regression equation is Delta/ (470 nm) = 24.3 C + 13.8 with a correlation coefficient of 0.9959. This method was applied to screening the antioxidants with satisfactory results.