Modified Glass Carbon Electrode (GCE) Electropolymerized Polypyrrole Nanofibers with Hemoglobin (Hb) Film as a Unique Biosensor for Nitrite Determination

In this study, we were investigated behavior the electrochemical reduction of nitrite at a hemoglobin (Hb) immobilized on glass carbon electrode (GCE) containing polypyrol nanofiber (ppy) films. Polypyrrole (PPy) nanofibers have been constructed on GCE applying electrochemical technique, and can to deposit diverse polymers on miniaturized electrodes with this common method. The structure of the acquired electrode and the electrochemical behavior were characterized using Scanning Electron Microscopy (SEM), Cyclic Voltammetry (CV), and Linear Sweep Voltammetry (LSV). The immobilized Hb showed an irreversible reduction peak with a formal potential of – 0.72 versus Ag/AgCl, in 0.1M pH 4.5 acetate buffer. The immobilized Hb exhibited remarkable electrocatalytic activity for the reduction of nitrite. Under the optimal condition the nitrite concentrations range 2.0×10−4 to 46.0×10−4 M with a detection limit of 6.2×10−5 M (at S/N=3). The resulting biosensor has been successfully applied to the determination of nitrite in water samples. The produced modified electrode for nitrite determination has been explored within the presence of the interfering substances including a number of common ions and cations, demonstrating great selectivity.