Carbon nanotube/carbon fiber electrodes via chemical vapor deposition for simultaneous determination of ascorbic acid, dopamine and uric acid

A promising and low-cost electrochemical sensor was carried out with carbon nanotube modified carbon-fiber electrodes via vapor deposition method, which improved the sensitivity and reduced the detection limit of dopamine. In virtue of various techniques, such as SEM and Raman spectroscopy, the morphological, structural and crystalline properties of composites were analyzed. Moreover, simultaneous determination of dopamine, ascorbic acid and uric acid was explored at the modified carbon fiber electrode. The presence of carbon nanotubes on the surface of carbon fiber can effectively increase the surface area and electron transfer velocity of the interaction between neurotransmitter and electrode. The good linear responses of ascorbic acid, dopamine and uric acid were obtained in the range of 25.6–2000.3 μM, 5.0–120.6 μM and 20.0–800.0 μM with detection limits (S/N = 3) of 10.0 μM, 0.03 μM and 0.6 μM, respectively. Finally, this sensor was applied to the determination of dopamine in some real sample.