Selective Detection of Dopamine in Presence of Ascorbic Acid by Use of Glassy-Carbon Electrode Modified with Amino-β-Cyclodextrin and Carbon Nanotubes

A glassy carbon electrode modified with per-6-amino-beta-cyclodextrin (beta-CDNH2) and functionalized single-walled carbon nanotubes (SWCNT-COOH) was elaborated. This structure was investigated for the detection of dopamine acid (DA) in presence of ascorbic acid (AA). The sensor behavior was studied by cyclic voltammetry, square wave voltammetry and electrochemical impedance spectroscopy. The analysis results show that the electrode modification with CD derivative improves the sensitivity and selectivity of the DA recognition; the electrochemical response was further improved by introduction of SWCNT-COOH. The sensor shows good and reversible linear response toward DA within the concentration range of 7 x 10(-7)-10(-4) M with a detection limit of 5 x 10(-7) M.