Simultaneous determination of dopamine and its oxidized product (aminochrom), by hydrodynamic amperometry and anodic stripping voltammetry, using the metallic palladium and uranalyl hexacyanoferrate coated aluminum electrodes

In the present work, the development of an effective electroanalytical strategy for the simultaneous determination of dopamine (DA) and aminochrom (AC) using hydrodynamic amperometry and anodic stripping voltammetry (ASV) on the Al modified electrodes is described. For this purpose the Al electrode is plated with metallic palladium (Pd-Al) by simple dipping procedure and subsequently the uranyl hexacyanoferrate (K2UO2[Fe(CN)(6)]) is deposited electrochemically on the Pd-Al electrode from a UO22+ + Fe(CN)(6)(3-) solution. The Pd-Al electrode is used for hydrodynamic amperometric measurement of DA at constant electrode potential of 0.35 V in a stirred electrolyte solution. At fixed operational conditions, the calibration graph for amperometry was linear over the DA concentration range 1 x 10(-6) to 50 x 10(-6) M. The detection limit of DA was 4.1 x 10(-7) M. Whereas the decrease of the ASV current of the K2UO2 [Fe(CN)(6)]/Pd-Al electrode prepared in the presence of AC was the principal of the AC determination. This decrease was proportional to the AC concentration in the solution, during K2UO2 [Fe(CN)(6)]/Pd-Al electrode preparation and the calibration graph was linear over the concentration range 1 x 10(-6) to 35 x 10(-6) M of AC. The detection limit was 4.5 x 10(-7) M AC. (c) 2009 Elsevier B.V. All rights reserved.