Fabrication and Analytical Investigation of Reduced Graphene Oxide and Poly-L-Glutathione Based Voltammetric Sensor for the Individual and Simultaneous Determination of Purine Derivative and Metabolites


 Purine metabolites are recognized disease biomarkers and food quality inspecting parameters. As such, reliable electro-analytical strategies for the quantification of purine bases are indispensable from a clinical point of view. We propose an efficient voltammetric sensor based on reduced graphene oxide and poly-L-Glutathione modified glassy carbon electrode (GCE) for determination of purine bases such as Uric acid (UA), Xanthine (XA), Hypoxanthine (HX), and Theobromine (TB). Surface characterization of the GCE has been carried out via surface area determination, scanning electron microscopy, atomic force microscopy, Raman spectroscopy, attenuated total reflection spectroscopy, cyclic voltammetry, and electrochemical impedance spectroscopy. For simultaneous determination, the sensor offers a limit of detection of 1.83×10-7, 6.70×10-8, 2.12×10-7, and 1.14×10-6 mol L-1 for UA, XA, HX, and TB respectively. The practical utility of the sensor has been ascertained via analysis in real samples and the findings are validated using conventional analytical methods. Mechanistic aspects involved in the electrooxidation of analytes have been derived using scan rate studies. A wide concentration linear range with low limit of detection and successful applicability studies in tea, coffee, cocoa, and artificial physiological samples points toward the efficacy of the analytical assay in real sample analysis.