Simultaneous Investigation of Dopamine and Ascorbic Acid at Poly (Tryptophan) Modified Carbon Paste Electrode: A Cyclic Voltammetric Study

A stable modified carbon paste electrode based on the poly (tryptophan) film wasprepared by electrochemical polymerization technique using cyclic voltammetry. theproperties of the electrodeposited films, during preparation under different conditions andtheir stability were evaluated. it was found that the current response of da and aa weregreatly enhanced at this poly (tryptophan) modified carbon paste electrode. moreover, theanodic over-potential of aa was significantly reduced for about 150 mv (vs. sce) comparedwith that obtained at bare carbon paste electrode. the modified carbon paste electrode wasapplied to the study of electrocatalytic oxidation of da and aa which resolved theoverlapping of the anodic peaks of da and aa in 0.1 mol l-1 acetate buffer solution at ph6.5. the separation of the oxidation peak potentials for ascorbic acid–dopamine was about0.277 v. interference studies showed that the modified electrode exhibits excellent selectivitytowards da and aa.