Dual analyte detection of dopamine and uric acid via MWCNTs/WO₃-modified electrodes with tunable electrochemical responses

This work presents an electrochemical sensor constituted using multi-walled carbon nanotubes/tungsten trioxide (MWCNTs/WO₃) nanocomposite for sensitive and selective detection of actual dopamine (DA) and uric acid (UA). MWCNTs were prepared via pyrolysis, and the MWCNTs/WO₃ composite was synthesized through a co-precipitation method. Comprehensive characterization using XRD, XPS, Raman, FTIR, FE-SEM, HR-TEM, and EDS confirmed the formation, uniform dispersion, and strong interaction of WO₃ nanoparticles on the functionalized MWCNT surface. The modified glassy carbon electrode exhibited enhanced electrochemical performance toward DA detection, with differential pulse voltammetry revealing a wide linear range from 25 nM to 580 μM, high sensitivity (56.54 μA μM⁻¹ cm⁻²), and a low detection limit of 7.821 nM. The sensor also enabled simultaneous determination of DA and UA (5–25 μM and 50–250 μM, respectively) with clear peak separation. Furthermore, it exhibited high selectivity, reproducibility, and stability, achieving recovery rates of 99.17–100.7 % in human urine samples. These results highlight the potential of MWCNTs/WO₃ nanocomposite as a reliable platform for biomedical and analytical applications requiring precise DA monitoring.