Розроблено чутливий елемент вольт-амперометричного сенсора для визначення гідроген пероксиду на основі ІТО (оксид індію та стануму) електрода, модифікованого частинками MnO2 та плівкою SiO2. Поєднання частинок MnO2 з плівкою SiO2 як модифікатора ITO електрода, дозволяє детектувати Н2О2 за струмом його окиснення в діапазоні кон-центрацій 0,1-1,0 ммоль/дм3 з межею виявлення 0,09 ммоль/дм3. Це на порядок нижче, ніж на немодифікованому ІТО. Ви- значенню Н2О2 на ITO/MnO2/SiO2 електроді не заважають еквімолярні кількості аскорбінової кислоти, сечовини та тіосечовини.
Разработан чувствительный элемент вольт-амперометрического сенсора для определения пероксида водорода на основе ИТО (ок-сид индия и олова) электродов, модифицированных частицами MnO2 и пленкой SiO2. Сочетание частиц MnO2 с пленкой SiO2 в качестве модификатора ИTO электрода позволяет детектировать Н2О2 по току его окисления в диапазоне концентраций 0,1-1,0 ммоль/дм3 с пределом обнаружения 0,09 ммоль/дм3. Это на порядок ниже, чем на немодифицированном ИТО. Определению Н2О2 на ИTO / MnO2 / SiO2 электроде не мешают эквимолярного количества аскорбиновой кислоты, мочевины и тиомочевины.
Nanostructured transition metal oxide nanoparticles possess a catalytic activity to hydrogen peroxide. M&anganese dioxide particles are one of the promising and available modificators of the electrode surface. Nanostructured MnO2 deposited onto the surface of the electrode enhances the electron transport from the H2O2 molecule to the surface. Thus selec&tivity and sensitivity of H2O2 detection can be improved. There are a lot of different methods of the impregnation of manganese dioxide particles onto electrode surface. An electrophoretic deposition is one of the most simple and rapid. By adjusting &the electrodeposition parameters, particles of different sizes or films can be obtained. A simple and novel hydrogen peroxide sensor based on layer-by-layer assembly of MnO2 nanoparticles and SiO2 film on the ITO electrode was developed. For this pur&pose MnO2 nanoparticles were electrodeposited on the surface of ITO electrode from MnSO4/CH3COOK solution. The electrochemical characteristics of the modified electrodes were investigated by cyclic voltammetry.The presence of MnO2 on the surface of m&odified electrode was indicated by the appearance of clear oxidation-reduction peaks of Mn(IV)/Mn(III,II) at E=0,65 V in the electrolyte solution in contrast to unmodified electrode. Optimization of measurement parameters such as the amount of MnO2, &applied potential and pH value were studied in details. Under the optimum conditions, the calibration curve for H2O2 determination using modified electrode was linear in the range from 1?10?4 to 1?10?3 mol/dm3 with a detection limit of 0,09?10?4 mol/&dm3 (S/N = 3). The linear rang for non-modified electrode was from 1?10?3 to 1?10?2 mol/dm3 with a detection limit of 1,8?10?4 mol/dm3 (S/N = 3). The modified ITO electrode was characterized by higher current than non modified ITO as a result of incr&easing of electroactive surface area and catalytic effect of electrodeposited MnO2.For the stabilization of MnO2 particles and protection of the electrode surface from impurities, the ITO/MnO2 was covered by thin silica film. The selectivity of H2O2 &determination at ITO modified with MnO2/SiO2 was better than at ITO especially in the presence of ascorbic acid which is oxidized at the same potential as H2O2. The oxidation current of ascorbic acid was much higher than H2O2 at nonmodified ITO in co&ntrast to ITO modified with MnO2/SiO2. The developed ITO electrode modified with MnO2/SiO2 is a perspective element of amperometric sensor for the detection of hydrogen peroxide.
