A sensitive resonance scattering spectral assay for the determination of trace H2O2 based on the hrp catalytic reaction and nanogold aggregation.

Gold nanoparticles in size of 15 nm exhibit a resonance scattering (RS) peak at 580 nm, in pH 6.4 citrate buffer solutions. Horseradish peroxidase (HRP) strongly catalyzed the H2O2 oxidation of o-phenylenediamine to form an intergradation of cyclohexa-3, 5-diene-1, 2-diylidenediamine and the product of 2, 3-diaminophenazin. Both cause gold nanoparticles aggregations to enhance the RS intensity at 580 nm greatly. Under the optimal conditions, the concentration of H2O2 (C) in the range of 0.08-2.2 micromol/l was proportional to the enhanced RS intensity at 580 nm (DeltaI580 nm). Its regression equation was DeltaI580 nm=46.8C+3.4, with a correlation coefficient of 0.9983 and a detection limit of 0.03 micromol/l H2O2. This new RS spectral method was applied to the determination of H2O2 in water samples with satisfactory results.