Rapid spectrophotometric detection of hydrogen peroxide using (Au)core (Ag)shell nanoparticle

Using 10 nm nanogold as seeds, the (Au)core (Ag)shell nanoparticles were prepared in the presence of AgNO3 and trisodium citrate dehydrate, and they were purified by high-speed centrifugation to remove the excess trisodium citrate. The absorption peak of the purified (Au)core (Ag)shell nanoparticles is at 393 nm. In pH = 4.4 HAc-NaAc buffer solution, hydroxyl radical produced from Fenton reaction oxidized the outer silver layer of the nanoparticles to form Ag+, and resulted in decreasing of the absorbance value at 393 nm. The concentration of H2O2 in the range of 6.58-421.1μmol/L was linear to the decreased absorbance at 393 nm (ΔA393nm). Its regression equation was ΔA393nm = 0.00111c + 0.0210, and the correlation coefficient was 0.9908, with a detection limit of 1.73μmol/L. This method was applied to the detection of H2O2 in wastewater, with satisfactory results.