Multi-walled carbon nanotubes doped with boron as an electrode material for electrochemical studies on dopamine, uric acid, and ascorbic acid

Boron-doped multi-walled carbon nanotubes (B-MWCNTs) were deposited on oxidized silicon substrate via decomposition of ethanol and boric acid in the presence of the catalyst ferrocene by means of chemical vapor deposition in a thickness of typically 900 nm. The B-MWCNTs were characterized using Raman spectroscopy and scanning electron microscopy and transmission electron microscopy in combination with energy dispersive X-ray spectroscopy. The deposited B-MWCNTs were electrochemically characterized using the ferrocyanide/ferricyanide redox system by means of cyclic voltammetry and electrochemical impedance spectroscopy. The response of B-MWCNTs towards oxidation of dopamine (DA), uric acid (UA), and ascorbic acid (AA) was studied. DA, UA and AA can be determined at working potentials of typically 0.267, 0.412, and 0.127 V (vs. Ag/AgCl) with detection limits of 0.11, 0.65, and 1.21 mu M, respectively.