Highly sensitive and selective voltammetric determination of dopamine using a gold electrode modified with a molecularly imprinted polymeric film immobilized on flaked hollow nickel nanospheres

The authors describe the preparation of a molecularly imprinted polymer (MIP) film on the surface of electrodeposited hollow nickel nanospheres (hNiNS), and the use of this nanocomposite in an electrochemical sensor for dopamine (DA). The use of the 3-dimensional hNiNS as a support material enlarges the sensing area and conductivity, while the MIP film warrants improved selectivity for DA. Quantification based on the "MIP/gate effect" was performed by employing hexacyanoferrate as the electrochemical probe. Scanning electron microscopy, cyclic voltammetry and electrochemical impedance spectroscopy were applied to characterize the sensor materials. The electropolymerization condition such as pH value, functional monomer and ratio of template to monomer were optimized. By using dopamine (DA) as a model analyte, the sensor, if operated at 0.1 V vs. SCE, has fairly low detection limit of 1.7 × 10⁻¹⁴ M (at an S/N ratio of 3), two wide assay ranges of 5 × 10⁻¹⁴ to 1 × 10⁻¹² M and 1 × 10⁻¹² to 5 × 10⁻¹¹ M, and superb selectivity.