Imprinted electrochemical sensor for dopamine recognition and determination based on a carbon nanotube/polypyrrole film

An electrochemical sensor combining a molecular imprinted technique and an electropolymerization method was developed in this work. A molecular imprinted polymer (MIP) film was fabricated by electropolymerizing pyrrole in the presence of dopamine (DA) after electrodepositing carboxyl-functionalized multi-walled carbon nanotubes (MWNTs-COOH) onto a glassy carbon electrode (GCE) surface. Scanning electron microscopy (SEM), differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS) were employed to characterize the constructed sensor. The effects of pH, the monomer concentration, the number of cycles for the electropolymerization, and the scan rate for the sensor preparation were optimized. The MIP-based sensor displayed an excellent recognition capacity toward DA compared with other structurally similar molecules. Additionally, the DPV peak current was linear to the DA concentration in the range from 6.25 × 10−7 to 1 × 10−4 mol/L, with a detection limit of 6 × 10−8 mol/L. The prepared sensor also showed stable reproducibility and regeneration capacity.