Determination of Hydrogen Peroxide Residue in Food Using CdS Quantum Dots as Fluorescence Probes

A simple and accurate method for determination of hydrogen peroxide (H2O2) using carboxymethyl cellulose coated CdS quantum dots (QDs) as a fluorescence probe was established. The influence factors of the fluorescence quenching system and the optimum conditions were investigated for analysis of hydrogen peroxide. It was found that the maximum relative fluorescence quenching intensity produced at pH 8.5 in 0.035 mol/L KH2PO4-Na2HPO4, when the concentration of CdS QDs was 1.9x10-3 mol/L and the reacting time and temperature were 45 minutes and 30 degrees C, respectively. Under the optimum conditions, the relative fluorescence quenching intensity has a linear relationship with the logarithmic concentration of H2O2 in the range from 3x10-5 to 5x10-2 mol/L. The limit of the detection is 2.3x10-6 mol/L for H2O2. The method was used to determinate the amount of remained H2O2 in milk and Calcium Tablets successfully.