Electrochemical Behaviours of Daidzein at Multi-Wall Carbon Nanotubes Modified Glassy Carbon Electrode

A simple and sensitive analytical method is presented for voltammetric determination of daidzein based on its electrochemical oxidation at a multi-wall carbon nanotube modified glassy carbon electrode ((MWCNT/GCE). Compared with bare glassy carbon electrode, the MWCNT/GCE exhibited excellent catalytic and enhancement effect on the electrochemical oxidation of daidzein. A series of parameters including supporting electrolyte, pH of supporting electrolyte, scan potential and scan rate were optimized. Under the optimal conditions, the linear range of daidzein concentration was 6.0 x 10(-6)-1.0 x 10(-4) mol/mL (R = 0.9991) with a detection limit of 7.2 x 10(-7) mol/L (S/N = 3), and the RSD for 2.8 x 10(-5) mol/L daidzein solution was 1.8 % (n = 11). This method was successfully used in the determination of daidzein in tablet. The mechanism investigation showed that the reaction of daidzein at the modified electrode was a process with one proton and one eletron transfer.