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

Abstract

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 (ΔI 470 nm) is linear with respect to the concentration of H2O2 (C) in the range of 0.27–7.56 μmol/L with a detection limit of 0.23 μmol/L. Its regression equation is ΔI 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.