A review on recent advancements in electrochemical detection of dopamine using carbonaceous nanomaterials

Dopamine (DA) is one of the most important neurotransmitters of catecholamines (epinephrine, adrenaline, etc.) in the central nervous system of mammals. Abnormalities in the DA levels of the body lead to multiple dysfunctions and numerous diseases. Among different scientific approaches, electrochemical sensing has proven to be an accurate, low-cost, quick, and easy technique that permits trace-level DA detection. Carbonaceous compounds have become a prevalent research topic as very efficient and low-cost materials for DA electrochemical sensors. Herein, published works, devoted to carbonaceous electrodes employed for dopamine electrochemical sensing, are reviewed and critically discussed. Among them, are included graphene-based and carbon-based electrodes alone and combined with non-noble metal/metal oxide nanoparticles or modified with conducting polymers (CPs) or doped with heteroatoms (like nitrogen, boron, and phosphorous). According to the present review study, the inclusion of a conducting polymer into the carbonaceous substrates results in very low limits of detection and enhanced sensitivity. In contrast, the addition of metal/metal oxide nanoparticles (NPs) in the carbonaceous support improves the electron transfer rate, increasing the selectivity to DA and offering remarkable oxidation peak separation ability, when interfering agents coexist. Moreover, the combination of two modifiers has also proven to be beneficial. Additionally, some disadvantages are also mentioned, including the difficulty of maintaining the same morphology of metal NPs in different batches of materials and also the challenge in reproducing CPs-modified electrodes. Moreover, the DA oxidation mechanism onto the different electrodes is discussed.