Electrochemical Biosensor based on Carbon Nanofibers and Diamine Oxidase for Detection of Norepinephrine

A novel biosensor based on carbon nanofibers/diamine oxidase was prepared by modification of screen-printing electrodes. The enzyme diamine oxidase was immobilized onto the carbon nanofibers modified carbon screen-printed electrodes by drop and dry method followed by cross-linking reaction with glutaraldehyde. The presence of norepinephrine in analyzed samples was correlated to increasing of cathodic current at -0.60 V. The procedure for preparation of biosensor was optimized. Furthermore, the experimental parameters affecting the sensitive properties of biosensors were optimized. In optimal conditions of pH and potential applied, the amperometric biosensor was characterized. The biosensor shows low detection limit (0.23 mM), good repeatability, and high affinity to norepinephrine ( app M K = 21.5 mM) demonstrating good quality performances of the biosensor. In addition, the Hill coefficient (h = 1.02) indicates a Michaelis-Menten kinetics of the enzymatic reaction. The biosensor was validated by standard addition method and was applied to the quantification of norepinephrine in pharmaceutical samples.