Synergistic Ternary Carbon Composite for Enhanced Simultaneous Electrochemical Sensing of Ascorbic Acid, Dopamine, and Uric Acid

Simultaneous quantification of ascorbic acid, dopamine, and uric acid is crucial for clinical diagnostics. Here, an electrochemical sensor was developed by modifying a glassy carbon electrode with a ternary composite of multi-walled carbon nanotubes, graphene, and Vulcan XC72 carbon black via a simple mixing method. The synergistic interaction of these carbon materials significantly increases the electroactive surface area and introduces defect-driven catalytic sites, enhancing electron transfer kinetics. The sensor enables interference-free simultaneous detection, exhibiting linear ranges of 100–1000 μM ascorbic acid, 5–50 μM dopamine, and 10–100 μM uric acid with sensitivities of 0.044, 0.47, and 0.95 μA μM−1, respectively, and corresponding limits of detection of 34.1, 4.23, and 11.1 μM. The platform also demonstrated excellent stability, reproducibility, and anti-interference performance, with satisfactory recoveries in human urine samples. These results highlight the ternary composite sensor as a reliable and practical tool for multiplexed monitoring in complex physiological matrices.