Chemically Modified Carbon Sensor for the Sensitive Electrochemical Analysis of Neurotransmitter Dopamine

The present paper reports an auramine O (AO) modified carbon paste electrode (P(AO) MCPE) as a sensitive electrode for the detection of dopamine. The study of the surface of both the unmodified and P(AO) MCPE sensors was done by cyclic voltammetry, scanning electrode microscopy, and electrochemical impedance spectroscopy. The analysis of dopamine in pH 6.5 showed transfer for two electrons and protons with a diffusion-controlled process. The good limit of detection of 0.092 μM was obtained for the linear range of 0.2–9.0 μM. The electrode depicted anti-interference property, along with good repeatability, reproducibility, and stability. The selective property of P(AO) MCPE towards dopamine in the presence of riboflavin makes it a more reliable sensor. The detection of dopamine in the injection sample gave satisfactory results, which suggests the applicability of P(AO) MCPE on real samples.