Electrochemical Determination of Norepinephrine on Cathodically Pretreated Poly(1,5‐diaminonaphthalene) Modified Electrode

A sensitive and simple electrochemical method for norepinephrine (NE) determination was developed based on a poly(1,5‐diaminonaphthalene) film electrode (PDAN). Cathodically pretreated PDAN presents good selectivity, sensitivity, and reproducibility for NE. The polymer film can be easily electropolymerized onto a platinum electrode by cyclic voltammetry in 1.0 M HClO₄. A cathodic pretreatment, consisting of the application of a potential of ?0.7 V for 3 s (vs. Ag/AgCl) to PDAN before each voltammetric measurement, enhanced the electrochemical activity of NE with no inference of ascorbic acid (AA). In optimized conditions, PDAN presents linear responses for NE in the range of 9.90 to 90.9 µM by differential pulse voltammetry (DPV) with a detection limit of 1.82 µM. A relative standard deviation of 3.0 % was obtained for 10 consecutive measurements of 40.0 µM NE solutions. The cathodically pretreated PDAN was successfully applied for NE determination in pharmaceutical formulation samples.