银掺杂改性蒙脱土修饰电极上对苯二酚的电化学行为与测定

Electrochemical Behavior and Determination of Hydroquinone on Silver/Treated Montmorillonite Modified Glassy Carbon Electrode

利用十八烷基三甲基溴化铵（STAB）和银氨溶液制备了银掺杂改性蒙脱土，并用X射线衍射法、扫描电镜法和交流阻抗法对其进行表征。用循环伏安法（CV）研究了对苯二酚在银掺杂改性蒙脱土修饰电极上的电化学行为，测定了部分动力学参数。结果表明，对苯二酚在电极上的阳极过程受吸附-扩散混合控制，阴极过程受扩散控制，转移的电子数n和质子数m均为2，传递系数α=0．6588，β=0．3412，电极有效面积Aeff=0．0264cm^2，扩散系数D=6．34×10^-5cm^2／s。用方波伏安法（SWV）研究了对苯二酚浓度与峰电流之间的线性关系，在优化实验条件下，对苯二酚浓度在4．0×10^-6-5．0×10^-4mol／L范围内与峰电流呈线性关系，检出限为1．13×10^-7mol／L，用该方法测定了实际水样中对苯二酚的含量，加标回收率为100％～108％。该修饰电极具有良好的重复性与稳定性。

A silver doped modified montmorillonite was made by octadecyl trimethyl ammonium bromide（STAB） and [Ag（ NH3 ） 2 ] OH, and characterized by X-ray diffraction, scanning electron microscopy and AC impedance method. The electrochemical behavior of hydroquinone on the electrode modified by the montmorillonite was investigated by cyclic voltammetry（CV） and some important kinetic parameters of the electrochemical process were determined. The results indicated that the anode process of hydroquinone at electrode was controlled by adsorption - diffusion, and the cathodic process was controlled by diffusion. The number of electron transfer was equal to the number of protons （ n = m = 2）, and the transfer coefficients a equals 0. 658 8 and 13 equals 0. 341 2. The effective area of Ag STAB -MMT/GCE（Aeff） was 0. 026 4 cm^2, and the diffusion coefficient（D） was 6. 34 × 10-s m^2/s. The correlation between the peak current and concentration was investigated by square wave voltammetry（,SWV）. A good linearity was obtained between the peak current and the concentration of hydroquinone in the range of 4.0 × 10^-6 - 5.0 × 10^-4 mol/L, with a detection limit of 1.13 × 10^-7 mol/L. The method was applied in the determination of hydroquinone in real water with spiked recoveries of 100% - 108% . The modified electrode showed good reproducibility and stability.