Studies on the Electrochemical Behaviors of Epinephrine at a Poly(l-aspartic acid) Modified Glassy Carbon Electrode and Its Analytical Application

The electrochemical behaviors of Epinephrine (EP) on a poly(l-aspartic acid) membrane are studied by cyclic voltammetry and electrochemical impedance spectroscopy (EIS). The poly(l-aspartic acid) membrane exhibited excellent electrocatalytic activities for the oxidation-reduction reactions of epinephrine, and in eliminating the interference of ascorbic acid (AA) and uric acid (UA). The anodic peak current of EP is linear with its concentration in the range of 1.0x10(-7)similar to 1.0x10(-5) mol L-1 and 1.0x10(-5)similar to 1.0x10(-4) mol L-1. The detection limit is 4.6x10(-8) mol L-1 (S/N=3). Compared with other electrochemical methods, this method has relative low detection limit and broad linear range. The practical application of the proposed method is demonstrated by determining the concentration of EP in pharmaceutical injections and the recovery tests. Some electrochemical parameters involved in the electrode reactions of EP, such as parameters of kinetic n alpha, standard rate constant of the electrochemical reactions k(s) and the number of H+, are also calculated.