Fabrication of a novel electrochemical sensor for determination of hydrogen peroxide in different fruit juice samples

A new hydrogen peroxide (H202) sensor is fabricated based on a multiwalled carbon nanotube-modified glassy carbon electrode (MWCNT-GCE) and reactive blue 19 (RB). The charge transfer coefficient, a, and the charge transfer rate constant, k(s), of RB adsorbed on MWCNT-GCE were calculated and found to be 0.44 +/- 0.01 Hz and 1.9 +/- 0.05 Hz, respectively. The catalysis of the electroreduction of H2O2 by RB-MWCNT-GCE is described. The RB-MWCNT-GCE shows a dramatic increase in the peak current and a decrease in the over voltage of H2O2 electroreduction in comparison with that seen at an RB modified GCE, MWCNT modified GCE, and activated GCE. The kinetic parameters such as a and the heterogeneous rate constant, k', for the reduction of H2O2 at RB-MWCNT-GCE surface were determined using cyclic voltammetry. The detection limit of 0.271AM and three linear calibration ranges were obtained for H2O2 determination at the RB-MWCNT-GCE surface using an amperometry method. In addition, using the newly developed sensor, H2O2 was determined in real samples with satisfactory results. Copyright (C) 2015, Food and Drug Administration, Taiwan. Published by Elsevier Taiwan LLC. This is an open access article under the CC BY-NC-ND license (http.//creativecommons.org/licenses/by-nc-nd/4.0/).