Amperometric sensing of dopamine using a single-walled carbon nanotube covalently attached to a conical glass micropore electrode

A single-walled carbon nanotube (SWNT) is covalently attached to the interior surface of a conical glass micropore electrode (GME) to create a novel amperometric dopamine sensor (SWNT/NH-GME). The SWNT/NH-GME combines the advantages of excellent transport properties of the cone-shaped micropore with the characteristics of a SWNT, exhibiting a dramatic electrocatalytic effect on the oxidation of dopamine (DA). Cyclic voltammetry and amperometric methods were employed to study the electrochemical behavior of the SWNT/NH-GME. The results showed that the SWNT/NH-GME sensor exhibited an excellent immunity from ascorbic acid interference and was able to measure DA concentrations with a detection limit of 4.2 × 10−7 mol/L (S/N = 3).