肉桂酸在玻碳电极上的电化学行为

Electrochemical Behaviours of Cinnamic Acid on Glassy Carbon Electrode

采用循环伏安法和计时库仑法等电化学方法研究了肉桂酸在玻碳电极上的电化学行为。在0．2mol·L^-1（pH=5．5）的B-R缓冲溶液中，肉桂酸在-0．912V（vs．SCE）处有一个不可逆的还原峰。考察了溶液pH值和扫描速度等因素对肉桂酸的电化学行为的影响。利用电化学法求出肉桂酸的扩散系数为4．88×10^-4cm^2·s^-1，传递系数0．33，推导了电化学还原方程式。在最佳条件下，肉桂酸浓度在5．0×10^-6～4．5×10^-5mol·L^-1范围内与还原峰电流ip值成线性关系，线性回归方程为ip（μA）=0．0453c（μmol·L^-1）＋7．914（n=8，γ=0．996），检测限为4．0×10^-6mol·L^-1。

The electrochemical behaviours of cinnamic acid on glassy carbon electrode （GCE） were studied by cyclic voltammetry and chronocoulometry. In 0. 2 mol · L^-1 Britton-Robinson buffer solution （pH=5.5）, cinnamic acid had an irrevevsible cathodic peak at -0. 912 V（vs. SCE）. The effects of factors such as pH value, scanning rate and concentration of cinnamic acid on the electrochemical behaviours of cinnamic acid were investigated. The diffusion coefficient D of cinnamic acid and the transfer coefficient was calculated as 4.88× 10^-4 cm^2 · s^-1 and 0.33 respectively. The electrode reduction mechanism was discussed. Under the optimum conditions a linear relationship between peak current and concentration of cinnamic acid was obtained in the range of 5.0× 10^-6～4.5×10^-5 mol · L^-1 of cinnamic acid. The linear regression equation was ip（μA）=0. 045 3c （μmol · L^-1 ） ＋ 7.914（n=8, γ=0. 996） and the detection limit was 4. 0× 10^-6 mol · L^-1.