Determination of hydrogen peroxide residues in aseptically packaged beverages using an amperometric sensor based on a palladium electrode

A novel amperometric sensor based on a palladium (Pd) electrode was developed to detect the hydrogen peroxide residues in aseptically packaged beverages. Amperometric measurements were performed using a laboratory-built potentiostat. The response characteristics and sensitivity of a Pd strip electrode and a screen printed carbon electrode (SPCE) to hydrogen peroxide levels in commercial beverages were compared. The difference between the baseline and the steady state current in the electrode was used to calculate the concentration of H2O2. The response of the SPCE with Pd electro-deposition to H2O2 in the reaction cell was linear over the range of 0.15-75 mu M (r(2) = 0.9985), suggesting its suitability for measuring the H2O2 residue in aseptically packaged beverages. Good correlations were found between H2O2 concentrations assessed using the proposed method: r(2) = 0.9976 for winter melon flavored drink (which did not contain ascorbic acid) and r(2) = 0.9987 for lemon flavored tea (containing ascorbic acid). Filtration of the sample beverage before the determination of H2O2 was required to avoid fouling on the surface of the electrode due to the deposition of insoluble compositions in the beverages. The characteristics of the developed SPCE sensor with Pd electro-deposition suggest its potential for use in devices to determine H2O2 residues in various aseptically packaged beverages, including those which contain interfering substances. (c) 2007 Elsevier Ltd. All rights reserved.