Fabrication of novel shape Cu and Cu/Cu₂O nanoparticles modified electrode for the determination of dopamine and paracetamol

In this paper, we demonstrate and compare the synthesis of copper (Cu) and copper(I) oxide on Cu (Cu/Cu₂O) nanoparticles via thermal decomposition method using a combination of oleic acid and oleylamine and oleic acid alone. Using a combination of oleic acid and oleylamine, involves a single nucleation step and control in growth of nanoparticles produces high monodispersity in shape and protects the copper nanoparticles against oxidation. X-ray diffraction (XRD) confirms the formation of single phase Cu only and X-ray photoelectron spectroscopy (XPS) evidences the formation of Cu without any formation of oxides on surfaces for over a long period of time with good stability. In view of interest in electrochemical sensors, we explore the fabrication of a novel and highly sensitive electrode and compare the electrochemical current responses for simultaneous determination of paracetamol and dopamine using Cu/Cu₂O nanoparticles stabilized by oleic acid alone and Cu nanoparticles obtained from a combination of oleic acid and oleylamine. Interestingly, we observe that Cu/Cu₂O nanoparticles stabilized by oleic acid alone exhibit excellent electrochemical enhancement in the peak current response towards simultaneous determination of paracetamol and dopamine with an increase in peak-peak separation of 239 mV. Differential pulse voltammetry (DPV) studies show a linear response to dopamine within the concentration from 0.02 μM to 0.159 μM with a detection limit of 3.27 nM (S/N = 3).