Ultrasensitive and selective dopamine detection using zirconia-decorated reduced graphene oxide nanocomposite via differential pulse voltammetry

Dopamine dysregulation is implicated in critical neurological disorders, including Parkinson’s disease, schizophrenia, and depression, necessitating rapid and precise quantification in clinical diagnostics. This work reports the fabrication of a high-performance electrochemical sensor employing a reduced graphene oxide–zirconium dioxide (rGO–ZrO 2 ) nanocomposite for the sensitive and selective detection of dopamine in physiological samples. The ZrO 2 –rGO nanocomposite was synthesized via a single-step hydrothermal route, and its structural, morphological, and optical characteristics were rigorously verified using UV–Vis spectroscopy, Fourier-transform infrared spectroscopy, and field-emission scanning electron microscopy. Electrochemical analysis, employing differential pulse voltammetry, revealed that the ZrO 2 –rGO-modified glassy carbon electrode exhibits enhanced electrocatalytic activity, enabling a linear detection range from 10 nM to 1 mM with ultra-low detection limits of 0.63 nM in phosphate-buffered saline and 2.36 nM in serum samples. The fabricated sensor exhibits remarkable selectivity, stability, reproducibility, and repeatability, enabling the quantification of dopamine in both buffer and serum samples. The outstanding analytical performance is attributed to the uniform dispersion of ZrO 2 and rGO within the nanocomposite, which augments electron transfer efficiency and catalytic responsiveness • ZrO 2 –rGO synthesized via one-pot hydrothermal and employed for the fabrication of a biosensor for Dopamine monitoring • ZrO 2 -rGO-modified biosensor showed superior response for dopamine with a wide linear range (10 nM–1 mM) and LODs of 0.63 nM (PBS) and 2.355 nM (serum). • Demonstrated excellent stability, reproducibility, and repeatability for dopamine detection in both buffer and biological matrices.