The Caw Modified Electrode Electrocatalytic Activity, Epinephrine, And Uric Acid

An investigation was carried out on electrocatalysis of the CAW (carbon atom wire) modified electrode to the electrochemical redox of adrenaline and uric acid, active physiological substances inside the human body, due to their important part played in life and medical sciences.Cyclic voltammetry combined with UV-vis spectrometry, and the forced convection method were applied in the investigation. As to the electrochemical response of redox of adrenaline/adrenalinequinone couple in 0.50 mol/L H₂SO₄, at a nitric acid treated CAW modified electrode, the anodic and cathodic peak potentials E_pa and E_pc shifted by 87 mV negatively and 139 mV in the positive direction, the anodic and cathodic peak current i_pa and i_pc increased by 5.6 and 16.4 times respectively, and standard heterogeneous rate constant k° increased by 16 times compared to the corresponding bare electrode, indicating the extraordinary activity of CAWs in electrocatalysis for the process. The redox process of adrenaline investigated by cyclic voltammetry combined with UV-vis spectrometry, is rather complicated, involving electron transfers coupled with chemical reactions, and strongly affected by the scan rate and the pH value in medium due to H⁺ involvement in some steps. It was also found that the anodic peak current on CVs of adrenaline in solutions with different concentrations at the CAW modified electrode had an excellent linear relation with the concentration of adrenaline within the range of 1.0×10^-4 - 1.0×10^-2 mol/L, with the detection limit of 2.0×10^-6 mol/L, implying the potential application of the modified electrode in determination of adrenaline.The electrochemical behavior of uric acid at the CAW modified electrode in different electrolytes was investigated by differential pulse voltammetry, showing high electrocatalytic activity of the modified electrode in the redox of uric acid. The slop in the linear relationship of anodic peak potentials and pH values, in the range of pH = 4-9, obtained from CVs of uric acid in solutions with different pH values at the CAW modified electrode, suggested that the electrode reaction involved the same numbers of proton and electron. The linear dependence of anodic peak currents on the square root of scan rates showed the redox of uric acid as a diffusion controlled process.