Amperometric determination of hydrogen peroxide residue in beverages using a Nafion modified palladium electrode

Hydrogen peroxide (H2O2) residues are not permitted in food due to health concerns. An amperometric sensor based on a Nafion modified palladium (Pd) electrode was developed for the rapid determination of the H2O2 residue in aseptically packaged beverages. A prepared Pd electrode shows a slowly increasing reaction upon repeating the procedure of adding the same concentration of H2O2 into the reaction cell unless pretreating the electrode with cyclic voltammetry to obtain reproducible surfaces, whereas a Nafion modified Pd electrode can reach stable reaction to H2O2 without any pretreatment. The interference level of ascorbic acid (the ration of electrochemical response to ascorbic acid to the electrochemical response of H2O2) was calculated as 0.0004 for the Nafion modified Pd electrode. Interference (99.5%)from ascorbic acid was diminished by Nafion membrane. The response of the sensor to H2O2 in distilled water is linear over the range of 0.25-15 mu M (r(2)= 0.9956). The sensor developed in this study can efficiently determine H2O2 residues in commercial beverages with good linear correlation between spiked H2O2 concentration and detected H2O2 concentration, for winter melon-flavored drink, r(2)= 0.9904 in the range of 0.25-15 mu M and for lemon-flavored tea, r(2)= 0.9927 in the range of 0.25-25 mu M.