Electrodeposited conducting polymer PEDOT doped with pure carbon nanotubes for the detection of dopamine in the presence of ascorbic acid

A highly stable and sensitive electrochemical sensor for the detection of dopamine (DA) was developed based on the electrodeposited conducting polymer, poly(3,4-ethylenedioxythiophene) (PEDOT), doped with pure carbon nanotubes (CNTs). The PEDOT/CNT nanocomposite was deposited on the carbon paste electrode through the electrochemical polymerization of PEDOT in the presence of CNTs as the only dopant. The electrochemical properties of the PEDOT/CNT film on the carbon paste electrode were characterized using cyclic voltammetry and differential pulse voltammetry. The PEDOT/CNT film showed high electrocatalytic activity toward the redox reaction of DA, and the redox peak current of DA at the PEDOT/CNT modified electrode was related to the DA concentration. A sensitive DA sensor was developed based on this excellent catalytic property, with a linear range from 0.1 to 20 μM, and a detection limit of 20 nM. This sensor is easy to fabricate, very stable and reusable, and free of interference from ascorbic acid (present at a concentration 1000 times higher than that of DA), all of which makes it a promising technology for DA sensing.