A Flexible Electrochemical Sensor Based on L-Arginine Modified Chemical Vapor Deposition Graphene Platform Electrode for Selective Determination of Xanthine

A flexible graphene platform electrode (GPE) was prepared by transferring chemical vapor deposition graphene film from Cu foil to polyethylene terephthalate substrate with the help of polymethyl-methacrylate. L -Arginine ( L -Arg) was electrodeposited on GPE to form a poly( L -Arg)/GPE (P( L -Arg)/GPE) which was characterized by scanning electron microscopy, energy dispersive spectroscopy and Raman spectroscopy. The electrocatalytic activity and enhanced conductivity of P( L -Arg)/GPE sensor was evaluated by determining xanthine (XA) in the presence of uric acid (UA) and hypoxanthine (HX) in phosphate buffer solution. The electrochemical behaviors of XA on P( L -Arg)/GPE were studied by cyclic voltammetry and differential pulse voltammetry in comparison with those on bare GPE. The proposed sensor not only achieved the selective determination of XA, but also separated the voltammetric signals of UA and HX with potential differences of 420 and 384 mV, respectively. Under the optimized conditions, the proposed sensor displayed superb sensing property towards XA in a wide linear range of 0.5-140 μmol/L with corresponding detection limit of 0.083 μmol/L ( S/N = 3). With good stability, reproducibility, high sensitivity, low cost as well as high resistance to interferences, the P( L -Arg)/GPE had been applied to determine XA in human serum successfully.