色氨酸在DNA-Pd混合纳米颗粒修饰玻碳电极上的电催化氧化作用

Electrocatalytic Oxidation of Tryptophan at a Glassy Carbon Electrode Modified with DNA-Pd Nanocomposites

以小牛胸腺DNA(ct-DNA)为模板,利用Pd^(2+)与DNA碱基之间的配位和结合作用提供稳定必需的化学环境,用电化学方法在玻碳电极上制备得到DNA-Pd混合纳米颗粒,用场发射扫描电子显微镜(FE-SEM)对所得产物进行表征,研究表明,该混合纳米颗粒具有独特、结构致密的花状结构,纳米粒子均匀分散在电极表面,并对色氨酸有很好的电催化氧化作用;色氨酸在DNA-Pd/GCE上的氧化过程有质子参与,是由扩散控制的电子传递过程。用差分脉冲伏安法(DPV)测定其氧化电流在色氨酸浓度9.99×10^(-7)~2.44×10^(-5) mol/L范围内呈线性关系,线性相关系数为0.999,检测限4.6×10^(-7) mol/L,该电极表现出较好的稳定性和选择性。

The ct-DNA was employedas template to prepare DNA-Pd particles.Owing to the coordination effect between Pd^(2+)ions and ct-DNA bases,the DNA template would provide a stable condition during the reduction process.A modified electrode was fabricated through electrochemical deposition method.The morphology of the electrode surface was characterized by field emission scanning electron microanalysis.The result indicated the formation of unique flower-like nanostruc⁃tures.The sensing ability was investigated by cyclic voltammetry(CV)and differential pulse voltammetry(DPV).The DNA-Pd/GCE had excellent catalytic activity toward the oxidation of tryptophan:good stability and excellent selectivity.The detection limit is found to be 4.6×10^(-7) mol/L and the linear concentration range is 9.99×10^(-7)~2.44×10^(-5) mol/L(R=0.999).