An Eletrochemical Quatrz Crystal Microbalance Study on Electrochemical Behavior of As(III) at Au/Au and Pt/Au Electrodes

作者：Huang Su-Qing; Huang Zhao; Gu Tie-An; Xie Qing-Ji^*; Yao Shou-Zhuo

来源：Chinese Journal of Analytical Chemistry, 2011, 39(7): 978-984.

DOI：10.3724/SP.J.1096.2011.00978

• Platinum/gold electrode
• Gold/gold electrode
• Electrochemical quartz crystal microbalance(EQCM)
• Electrochemistry of arsenic(III)

Electrochemical behavior of As(III) at Au/Au and Pt/Au electrodes was investigated with an electrochemical quartz crystal microbalance (EQCM) in Britton-Robinson (B-R, pH = 1.8-11.2) buffer solutions and in 0.1 or 0.5 mol/L aqueous H(2)SO(4). Through real-time process monitoring of the EQCM parameters (frequency etc.) and enhancement of the electrode-response signals by pre-electrodeposition of As (0), the electrodeposition of As (0), the electrode-surface-adsorption characteristics of As(III) and As(V), and the pH-dependence of the electrochemistry of As species were investigated. The following main conclusions are reached: (1) electrodeposition of As(0) can occur on both electrodes, but electrodeposition of As(0) on Pt/Au is more significant, and the electrooxidation of As(0) electrodeposited on Pt/Au at sufficient quantity can exhibit two current peaks for oxidation of outer-layer As(0) followed by inner-layer As(0); (2) As(III) can strongly adsorb on Pt/Au but its oxidation product as As(V) can desorb from the electrode surface, and the adsorption of both As(III) and As(V) is very weak on Au/Au; (3) the electrooxidation current of As(III) on Pt/Au tends to be the maximum in pH = 1.8 B-R buffer solution and in 0.1 mol/L aqueous H(2)SO(4). Based on the pre-adsorption of As(III) on Pt/Au and its catalyzed electrooxidation stripping, we proposed a new linear sweep voltammetric electroanalysis method for the determination of As (III), by which the detection sensitivity for As(III) can be 40-fold enhanced over the pre-adsorption-free case

• 出版日期2011-7
• 单位湖南师范大学