Preparation of peroxidase-based poly-L-histidine modified glassy carbon enzyme electrode for hydrogen peroxide determination

In this study, a new amperometric biosensor for the determination of hydrogen peroxide (H2O2) was prepared by electrostatic immobilization of horseradish peroxidase (HRP) on a multi-walled carbon nanotube (MWCNT), ionic liquid (IL) and poly-L-histidine (PLH) modified glassy carbon electrode (GCE). The surface morphology of the prepared biosensor was examined by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX), and its electrochemical properties were examined by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) methods. The electrode composition, buffer pH value and working potential were optimized to obtain the best analytical performance. The modified electrode prepared in optimum composition exhibited two different linear operating ranges of 2,0×10-2 μM – 9,1×10-1 μM and 1,80 μM – 1,80×102 μM at the optimum operating conditions. The limit of detection of the method was determined as 2,9×10-3 μM. It has been determined that the developed biosensor can be successfully applied in the amperometric determination of H2O2 in commercial oxygenated water sample.