Simultaneous electrochemical determination of uric acid and hypoxanthine at a TiO/graphene quantum dot-modified electrode.

A TiO/graphene quantum dots composite (TiO/GQDs) obtained by in situ synthesis of GQDs, derived from coffee grounds, and peroxo titanium complexes was used as electrode modifier in the simultaneous electrochemical determination of uric acid and hypoxanthine. The TiO/GQDs material was characterized by photoluminescence, X-ray diffraction, Raman spectroscopy, high-resolution transmission electron microscopy, and energy-dispersive X-ray mapping. The TiO/GQDs-GCE exhibits better electrochemical activity for uric acid and hypoxanthine than GQDs/GCE or TiO/GCE in differential pulse voltammetry (DPV) measurements.