Simultaneous electroanalysis of norepinephrine, ascorbic acid and uric acid using poly(glutamic acid) modified carbon paste electrode

A sensitive, selective and reproducible electrochemical method was developed for the electroanalysis of norepinephrine (NE) using poly(glutamic acid) modified carbon paste electrode. The modified electrode shows excellent electrocatalytic activity towards the oxidation of NE in phosphate buffer solution (PBS) of pH 7.4 by cyclic voltammetric and differential pulse voltammetric techniques. The lower limit of detection of NE was found to be 0.43 mu M. The interference studies showed that the modified electrode exhibits excellent selectivity in the presence of large excess of ascorbic acid (AA) and uric acid (UA). The separation of the oxidation peak potentials for NE-AA and NE-UA were about 0.262 V and 0.122 V. respectively. This peak differences were large enough to determine NE, AA and UA individually and simultaneously. This work provides a simple and easy approach to selectively detect NE in the presence of AA and UA. (C) 2015 Elsevier B.V. All rights reserved.