甲氧苄啶修饰玻碳电极安培法对过氧化氢的测定

在0.1 mol·L~(-1) KNO_3底液中,研究了甲氧苄啶在玻碳电极上的电化学性质,发现在0.140、0.177 V处出现1对可逆的氧化还原峰.进一步用电化学沉积的方法将甲氧苄啶修饰在玻碳电极上,考察了各种实验条件对修饰电极性能的影响,并通过电子扫描显微镜和电化学阻抗谱对修饰电极的表面性质进行了表征,所制得的修饰电极对过氧化氢的还原有很好的催化作用.在-0.3 V的工作电位下,用计时安培法对过氧化氢进行了测定,过氧化氢的浓度在1.96×10~(-5) ～1.10×10~(-3) mol·L~(-1)范围内与响应电流呈线性关系,检出限为4.0 μmol·L~(-1).该修饰电极制作简单、使用寿命长,实际试样的回收率为97% ～104%.

Amperometric Determination of Hydrogen Peroxide at Glass Carbon Electrode Modified by Trimethoprim

The electrochemistry characteristics of trimethoprim were studied by cyclic voltammetry in the solution of 0. 1 mol L~(-1) KNO_3. A pair of reversible peak of trimethoprim was observed at the position of 0. 140 V and 0. 177 V, respectively. Moreover, the modified glass carbon electrode was fabricated by the means of electrochemical deposition method in the solution of 4. 0 × 10~(-4) mol · L~(-1) trimethoprim. The electrochemical behavior of H_2O_2 on modified electrode was investigated by cyclic voltammetric and amperometric method. Under the optimal experimental conditions, the modified e-lectrode exhibited a significant electrocatalytic activity toward H_2O_2. Under the operating potential of -0. 3 V, the response current was linear with the concentration of H_2O_2 in the range of 1.96 × 10~(-5) -1. 10×10~(-3) mol · L~(-1) with a detection limit of 4.0 μmol · L~(-1). The modified electrode offered a highly sensitive and rapid response to H_2O_2, and was applied in the determination of real samples containing hydrogen peroxide with satisfactory recoveries of 97% - 104% .