Electrochemical investigation of p-chloranil as an organic mediator in determination of dopamine using of multiwall carbon nanotubes paste electrode

In this work, we study electrochemical behavior of p-chloranil as a suitable mediator for voltammetric determination of dopamine (DA) using voltammetric method. Using the modified electrode, the kinetics of DA electrooxidation was considerably enhanced by lowering the anodic over potential through a catalytic fashion. The differential voltammetric peak currents of the electrode increased linearly with the corresponding DA concentration in the range of 0.5-115 ?mol L-1 with a detection limit of 0.2 ?mol L-1. The influence of pH and potential interfering substances on the determination of DA were studied. The RSD% for 5 replicates determination of 100 ?mol L-1of DA were 1.5%. Finally, the sensor was examined as a selective, simple, and precise new electrochemical sensor for the determination of DA in real samples, such as drug and urine, with satisfactory results.