Electrocatalytic oxidation and determination of norepinephrine in the presence of ascorbic and uric acids at a poly (Evans Blue)—modified glassy carbon electrode

A sensitive and selective electrochemical method for the determination of norepinephrine using a poly (Evans Blue) film-modified glassy carbon electrode was developed. The polymer film-modified electrode shows excellent electrocatalytic activity toward the oxidation of norepinephrine (NE) in phosphate buffer solution (pH 5.0). The linear range of 5.0 × 10−7–1.8 × 10−5 M and detection limit of 3.5 × 10−8 M were observed for the determination of NE in pH 5.0 phosphate buffer solutions. The interference studies showed that the modified electrode had excellent selectivity for the determination of NE in the presence of large excess of ascorbic acid (AA) and uric acid (UA). The differences of the oxidation peak potentials for NE-AA and NE-UA were about 175 and 172 mV, respectively. The resolution is large enough to determine AA, NE and UA individually. This work provides a simple and easy approach to selective detection of NE in the presence of AA and UA in physiological samples.