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.