CeO2 nanocubes-based electrochemical sensor for the selective and simultaneous determination of dopamine in the presence of uric acid and ascorbic acid

In this work, CeO₂ nanocubes prepared by a simple co-precipitation method were employed for the determination of dopamine (DA) using an electrochemical method. The prepared material was characterized using morphological analysis like Transmission Electron Microscope (TEM) and the chemical structure was elucidated using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman and Fourier Transform Infrared (FTIR) spectroscopy respectively. From the TEM analysis, the growth of CeO₂ nanocubes into nanorods was observed and particle size was determined to be 10 nm. The presence of cubic crystalline structure was confirmed through XRD and the structural analysis was confirmed using FTIR and Raman spectroscopy. The oxidation state of the elements was confirmed through XPS analysis. For the electrochemical redox reaction of DA, the CeO₂-modified glassy carbon electrode (GCE) showed excellent catalytic activity towards the DA oxidation compared to bare GCE. The detection of DA using differential pulse voltammetry (DPV) showed a limit of detection (LOD) of 3.2 µM and a linear range of 10-300 µM, respectively. Similarly, for UA and AA, the detection limit and linear range were found to be 4.3 µM and 10 µM-700 µM for UA; 14 µM and 10 µM-250 µM, respectively for AA. The repeatability and reproducibility of the sensor were studied and the veracity of the sensor towards the estimation of DA in blood serum samples was analyzed. The admirable performance of the present biosensor could be potentially useful for biomedical applications.

Graphical abstract

CeO₂ nanocubes were prepared by a facile chemical method. The enhanced catalytic activity was exhibited by CeO₂ nanocubes towards the electro-oxidation of dopamine and excellent selectivity in the presence of uric acid and ascorbic acid.