Abstract:

Boron-doped diamond thin-film electrode was modified by the electrochemical reduction of aryl diazonium salt to attach aminophenyl group. X ray photoelectron spectroscopy（XPS）indicates the presence of N1s at the surface of electrode. By analyzing the peaks centered at 406 eV and 400 eV，XPS also suggests that nitrophenyl groups are electrochemically reduced to aminophenyl groups. The aminophenyl layer attached onto diamond thin-film electrode was demonstrated by comparing the voltammetric profiles of the Fe(CN)₆^－3/－4 redox couple at the electrode. The electrochemical behaviors of modified electrode were detected by differential pulse voltammetry（DPV）and cyclic voltammetry. The DPV for simultaneous determination of dopamine and ascorbic acid shows well-separated oxidation peaks with the potential difference about 0.3 V. The plasma protein adsorption at the surface modified electrode blocks electron transfer of Fe(CN)₆^－3/－4 redox couple. However，it does not affect the detection of dopamine.

摘要：

采用重氮盐电化学还原的方法对掺硼金刚石薄膜电极进行氨基化改性，光电子能谱（XPS）证明表面N元素的存在，同时可以通过406 eV、400 eV峰强度的变化，证明硝基还原为氨基。以Fe(CN)₆^－3/－4氧化还原电对为探针，进一步证明了氨基层的存在。采用循环伏安法和差分脉冲伏安法研究了改性后电极的电化学行为。通过分别检测多巴胺和抗坏血酸以及它们的混合溶液，表明选用差分脉冲伏安法，氨基化改性掺硼金刚石薄膜电极能够有效分离检测两者的氧化峰，分离后两峰电势差约为0.3 V。电极表面吸附血浆蛋白后，阻碍了Fe(CN)₆^－3/－4氧化还原对的电子传递，但是并不妨碍多巴胺的检测。