纳米Fe_3O_4修饰电极制备及其催化应用

Preparation of Fe_3O_4 Nanoparticle Modified Electrode and Its Electrocatalic Oxidation of Dopamine

制备了一种新型的纳米Fe3O4修饰电极,用电化学阻抗谱(EIS)和循环伏安法(CV)对该修饰电极进行表征。研究了多巴胺(DA)在该修饰电极上的电化学行为,结果发现,这种纳米粒子对DA的氧化具有良好的催化作用。在pH=6.0的磷酸缓冲溶液中,DA在该修饰电极上的氧化还原式电位为0.192V(vs.Ag/AgCl电极)。采用计时电流法测定DA,其氧化峰电流与浓度在1.5×10-7～4.0×10-4mol/L范围内呈线性关系,线性回归方程为ip(μA)=0.715+0.272c(μmol/L),相关系数λ=0.9981。检测限为3.0×10-8mol/L(S/N=3)。运用该方法测定多巴胺时,抗坏血酸干扰可基本被消除。

A novel gold electrode modified with Fe_(3)O_(4) nanoparticles was constructed and characterized by means of electrochemical impedance spectroscopy and cyclic voltammertry. The modified electrode exhibits strong promoting effect and high stability toward the electrochemical oxidation of dopamine(DA), which gives reversible redox peaks at a formal potential of 0.192 V(vs.Ag/AgCl) in a pH=7.0 phosphate buffer (solution). The anodic peak current(measured with constant potential amperometry) increass linearly with the increased concentration of dopamine in the range of 1.5×10^(-7) to 4.0×10^(-4) mol/L and the linear regression equation is i_(p)(μA)=0.715+0.272c(μmol/L). The detection limit (S/N=3) obtained was 3.0×(10^(-8) mol/L). The relative standard deviation(RSD) of 8 successive scans is 3.4% for 1.5×10^(-6) mol/L DA. The interference of ascorbic acid with the determination of DA could be eliminated efficiently. The proposed method shows excellent sensitivity and recovery.