Selective Determination of Epinephrine in the Presence of Ascorbic Acid and Dopamine at Silver Doped Polyglycine Modified Electrode

A silver doped polyglycine modified electrode was prepared by cyclic voltammetry. The electrochemical behavior of epinephrine at the modified electrode was studied. A novel method for determination of epinephrine using cyclic voltammetry was established. In pH=4.0 phosphate buffer solution, epinephrine gave an anodic peak at the modified electrode which can eliminate the interference of ascorbic acid and dopamine to the epinephrine determination. The peak potentials were Epa=0.399V and Epc=0.375V (vs Ag/AgCl). The anodic peak current versus the concentration of epinephrine showed a linear relations over the range of 5.60x10(-7)mol.L-1 similar to 1.00x10(-4)mol.L-1 with a correlation coefficient as follows:i(pa)=3.53x10(-6)+0.079c(mol.L-1),R=0.9979; The detection limit was 1.10x10(-7) mol.L-1. The recovery was 96.7%similar to 104.3%. The methods have been applied to injection sample analysis, and the results were in good agreement with the standard values.