Mohammad Bagher Gholivand, - Department of Chemistry, Faculty of Science, Razi University, Kermanshah, Iran۱
Masoud Amiri - Department of Chemistry, Islamic Azad University Of Kermanshah, Iran

A novel voltammetric method using the Ppy/Az/Au (poly pyrrole – aszophloxine – gold) modified electrode was developed for simultaneous measurement of various combinations of dopamine (DA) and acetaminophen (AC). Polypyrrole film was prepared by incorporation of aszophloxine (Az) as doping anion, during the electropolymerization of pyrrole onto a gold (Au) electrode in aqueous solution using cyclic voltammetric (CV) method, and then it was overoxidized at constant potential. Differential pulse voltammetry was utilized for the measurement of both analytes using modified electrode. Well-separated voltammetric peaks were observed for dopamine (DA) and acetaminophen (AC) Ppy/Az/Au modified electrodes with peak separation of 0.20 V. It has been found that under optimum condition (pH 3.0), the oxidation of DA and AC at the surface of the electrode occurs at a potential about 0.44 and 0.64 mV less positive than unmodified Au electrode respectively. The current catalytic oxidation peaks showed a linear dependent on the concentration of DA and AC in the range of 8.010-8 to 3.010-5 and 1.010-7to 1.010-4mol L-1 respectively. The detection limit of 5.0108 and 7.5 10-8 mol L-1(S/N=3) were obtained for DA and AC respectively. The modified electrode was used for determination of DA and AC in some real samples such as human serum and tablet.