Simultaneous electrochemical determination of norepinephrine, ascorbic acid and uric acid using a graphene modified glassy carbon electrode

This paper describes the simultaneous determination of ascorbic acid (AA), norepinephrine (NE) and uric acid (UA) using a graphene modified glassy carbon electrode (GME) in pH 4.0 phosphate buffer solution. The electrochemical behaviors of AA, NE and UA at a bare glassy carbon electrode (GCE) and the GME were studied by cyclic voltammetry. Bare GCE failed to resolve the voltammetric signals of AA, NE and UA in a mixture, whereas the GME not only resolved their voltammetric signals, but also exhibited excellent electrocatalytic activity towards their electrochemical oxidation. The oxidation peak currents of AA, NE and UA were linearly proportional to their concentrations over the range of 1.0.0-1000.0, 0.6-45.0 and 1.0-100.0 mu M, respectively, and their detection limits were 1.2, 0.10 and 0.60 mu M, respectively, The modified electrode is of excellent sensitivity and selectivity, and has been satisfactorily used for the simultaneous determination of AA, NE and UA in their ternary mixture.