Electrochemically selective detection of dopamine over serotonin by CuO/Cu₂O bulk heterostructure electrode

A facile single-pot electrochemical technique was adopted to deposit CuO/Cu₂O bulk heterostructure in the form of thin film on indium-doped tin oxide (ITO)-coated glass substrates aiming to explore its non-enzymatic electrochemical sensing performance of the two neurotransmitters, viz. dopamine (DA) and serotonin (ST). Thorough structural characterization of the deposited materials was carried out, followed by detailed electrochemical analyses towards the sensing of dopamine and serotonin in phosphate buffer solution. The sensitivity of the electrode was found to be 9.22 µA µM⁻¹ cm⁻² with a limit of detection (LoD) of 0.388 µM for dopamine. Whereas for serotonin, the sensitivity and LoD values were 1.18 µA µM⁻¹ cm⁻² and 8.11 µM, respectively. The results clearly indicates that the CuO/Cu₂O bulk heterostructure electrode is a better candidate for the electrochemical detection of dopamine, whereas its serotonin sensitivity was average. This makes the electrode more selective to dopamine.