Enhancement of Dopamine Electrochemical Detection with Manganese Doped Crystalline Copper Oxide

Manganese doped crystalline copper oxide (CuO:Mn) and undoped CuO were prepared at room temperature by the hydrothermal method. The complete physico-chemical characterization of the materials was performed using X-ray diffraction (XRD), transmission/scanning electron microscopy (TEM/SEM), and X-ray photoelectron spectroscopy (XPS). Furthermore, their analytical applicability was tested in electrochemical experiments for a dopamine assay. According to the morphological investigation, the materials had a flat structure with nearly straight edges. The XRD analysis proved the formation of the CuO phase with good crystallinity, while the Mn doping was determined by XPS to be around 1 at.%. Under optimized conditions, at pH 5.0, the CuO:Mn modified electrode (CuO:Mn/SPE) showed a high signal for dopamine oxidation, with a linear response in the 0.1–1 µM and 1–100 µM ranges and a low limit of detection of 30.3 nM. Five times higher sensitivity for manganese doped copper oxide in comparison with the undoped sample was achieved. The applicability of the developed CuO:Mn/SPE electrode was also tested in a commercially available pharmaceutical drug with good results, suggesting that the developed sensor has promising biomedical application potential.