Hydrogen Peroxide-Sensitive Amperometric Sensor Based on Manganese Dioxide Nanoparticles

A method for the synthesis of manganese dioxide nanoparticles in reverse micelles is developed and optimized. Nanoparticles are characterized by transmission electron microscopy. An amperometric sensor to detect hydrogen peroxide is developed based on thin films of the synthesized manganese dioxide nanoparticles. The possibility of its use for the electrochemical detection of hydrogen peroxide and its operational and longterm stability are examined. The effect of measuring the response potential, pH, and the ionic strength of solution, as well as of interfering compounds, on the results of hydrogen peroxide measurements are studied. The dependence of response values on the hydrogen peroxide concentration is obtained. The linear range of this dependence is in the interval from 7.8 x 10(-8) to 7.8 x 10(-4) M. The detection limit is 7.8 x 10(-8) M (3 sigma), and the sensitivity is 922 mA/(M center dot cm(2)). The possibility of using the proposed hydrogen-peroxide-sensitive sensor for producing more complex enzyme amperometric sensors based on oxide reductases is exemplified by a choline oxidase biosensor.