Integrated (Pt/PEDOT–Pt–Ag/AgCl) and (Au/PEDOT–Pt–Ag/AgCl) electrochemical microcells (ElecCell) were elaborated for the detection of ascorbic acid, dopamine and uric acid by differential pulse voltammetry. Specific attention was brought to the integration of poly(3,4-ethylenedioxythiophene) (PEDOT) film by electropolymerization. Gold and platinum working microelectrodes were investigated while using ethylenedioxythiophene (EDOT) electrodeposition processes in water or acetonitrile solvents. For the three antioxidant species, best (multi-)detection properties were obtained for acetonitrile-based PEDOT films deposited on gold working electrode. Thus, using integrated (Au/PEDOT–Pt–Ag/AgCl) Elec-Cell microdevices, analytical performances were determined for ascorbic acid, dopamine and uric acid, exhibiting high selectivity (oxidation potential: −40, 150 and 280 mV, respectively), linear concentration range from 0.1 to 300 µM, high sensitivities (0.85, 1.65 and 3.06 µA/ µM cm2, respectively) and low detection limit (0.2 µM, 0.1 µM and 0.05 µM, respectively).