Electrochemical Determination of Hydrogen Peroxide Using a Prussian Blue-Copper Modified Platinum Microelectrode

Abstract

Prussian blue modified with copper was electrodeposited on a platinum microelectrode for the amperometric determination of hydrogen peroxide at −50 mV. The Prussian blue-copper layer was stable for 2 h at pH 7.4 and a storage period of 2 months. The Prussian blue-copper modified microelectrodes were used to develop oxidase based microbiosensors for ethanol and lactate. Lactate and alcohol oxidases were immobilized by cross-linking with glutaraldehyde. No interferences were observed from possible interfering compounds up to a concentration of 0.5 mM. The calibration plot of the lactate microbiosensor was linear between 0.005 and 0.2 mM with a limit of detection of 0.0035 mM lactate. The linear dynamic range of the alcohol microbiosensor was between 0.05 and 2 mM and the limit of detection was 0.02 mM ethanol. The developed microbiosensors were used for the analysis of pickled cucumber juice, yogurt, and wine.