Herein, we report the construction of GO/Fe₃O₄@SiO₂ core–shell nanocomposite-modified graphite screen-printed electrode that shows advantageous characteristics in terms of electrical conductivity, catalytic activity and surface area compared to bare screen-printed electrode. The designed sensor was used for the determination of dopamine and uric acid. Cyclic voltammetry, differential pulse voltammetry and chronoamperometry methods were used as the diagnostics techniques. Using the modified electrode, dopamine and uric acid were determined in the concentration ranges from 0.1 to 600.0 μM and 0.75 to 300.0 μM, respectively, whereas the detection limits were found to be 8.9 × 10⁻⁸ M and 5.7 × 10⁻⁷ M, respectively. Finally, real sample analysis was done successfully using the modified electrode.