Simultaneous determination of ascorbic acid, dopamine and uric acid using PEDOT polymer modified electrodes

Dopamine, uric acid and ascorbic acid have been determined simultaneously on a poly(3,4-ethylenedioxythiophene) modified electrode using electrochemical techniques. On a bare glassy carbon electrode, all three undergo oxidation and appear as a single peak at around 200 mV, whereas on the modified electrode, distinct peaks with clear potential separation are observed, paving way for their simultaneous determination. Detection limits of 7.4 μM, 1.2 μM and 1.4 μM for ascorbic acid, dopamine and uric acid, respectively are observed by pulse voltammetry. The possible interference from creatinine, norepinephrine, epinephrine, glucose, ascorbic acid, urea, oxalate and acetylsalicylic acid (aspirin) has been tested. The protocol developed using this modified glassy carbon electrode has been evaluated using the human blood serum samples for the simultaneous determination of dopamine and uric acid.