Electrocatalytic Determination of Carbidopa and Acetaminophen Using a Modified Carbon Nanotube Paste Electrode

A carbon nanotube (CNT) paste electrode was constructed for the determination of carbidopa (CD). Owing to the unique structure and extraordinary properties of CNTs, the modified electrode has shown an obvious electrocatalytic activity towards oxidation of CD, which leads to lowering its overpotential by more than 400 mV. Also, the values of electron transfer (α=0.34)˛ and diffusion coefficient (D0=5.9×10-6 cm2/s) for CD were calculated. Under the optimum conditions, the oxidation peak currents were linearly proportional to the concentration of CD in the range from 0.07-600.0 μΜ. The detection limit was 29.0 nM. Then the modified electrode was used to determine CD in an excess of acetaminophen (AC). Finally, the proposed sensitive and simple electrochemical method was successfully applied to CD and AC determination in urine samples.