Simultaneous electrochemical detection of dopamine and paracetamol using a carbon paste electrode modified with neodymium oxide and prepared via hydrothermal treatment

In this report, hydrothermal treatment of a carbon-based electrode modified with neodymium oxide markedly enhanced the electroactive and conductive properties of the electrode. The results revealed that the particle size of the neodymium oxide and carbon paste mixture was more uniform and smaller after hydrothermal treatment, with the size range being reduced from 2000-10000 nm to 600-900 nm. This change increased the electrochemical activity of the simultaneous anodic current of dopamine and paracetamol by more than 100% compared with that of the neodymium oxide and carbon paste mixture that did not undergo hydrothermal treatment. The electroanalytical application of this new composite allowed the simultaneous detection of dopamine and paracetamol. The optimum pH value, accumulation potential, accumulation time, frequency and amplitude were found to be 3.5, 0.0 V, 30 s, 5 Hz and 0.05 V, which provided detection limits of 0.06 and 0.02 µmol L^-1, respectively. The composite was applied for the detection of real samples, namely, cold syrup for paracetamol detection and a human urine sample for dopamine detection.