Department of Chemistry, Faculty of Science, Yazd University, Yazd, 89195-741, I. R. Iran.
Analyst. 2011 May 7;136(9):1965-70. doi: 10.1039/c0an00823k. Epub 2011 Mar 9.
The electrooxidation of dopamine (DA), uric acid (UA) and their mixture on a gold electrode modified by a self-assembled monolayer of 2-(3,4-dihydroxyphenyl)-1,3-dithialone has been studied by cyclic voltammetry (CV), chronoamperometry and differential pulse voltammetry (DPV). CV was used to investigate the redox properties of the modified electrode at various scan rates and the apparent charge transfer rate constant (k(s)), and transfer coefficient (α) were calculated. The mediated oxidation of DA at the modified electrode under the optimum condition (pH = 7.0) in CV occurs at a potential about 220 mV less positive than that of the unmodified gold electrode. The values of electron transfer coefficients (α), catalytic rate constant (k) and diffusion coefficient (D) were calculated for DA, using electrochemical methods. DPV exhibited a linear dynamic range over the concentration range of 0.2-250.0 μM and a detection limit (3σ) of 0.07 μM for DA. The modified electrode was used for simultaneous determination of DA and UA by DPV. The results showed that the electrode is highly efficient for the catalytic electrooxidation of DA and UA, leading to a remarkable peak resolution (~350 mV) for two compounds. The electrode was used for the determination of DA in an injection sample.
通过循环伏安法（CV）、计时安培法和差分脉冲伏安法（DPV）研究了自组装单层 2-（3,4-二羟基苯基）-1,3-二硫酮修饰金电极上多巴胺（DA）、尿酸（UA）及其混合物的电氧化。CV 用于在不同扫描速率下研究修饰电极的氧化还原性质，并计算表观电荷转移速率常数（k(s)）和转移系数（α）。在 CV 中，在最佳条件（pH = 7.0）下，修饰电极对 DA 的介导氧化发生在比未修饰金电极正约 220 mV 的电位。使用电化学方法计算了 DA 的电子转移系数（α）、催化速率常数（k）和扩散系数（D）的值。DPV 在 0.2-250.0 μM 的浓度范围内表现出线性动态范围，对 DA 的检测限（3σ）为 0.07 μM。修饰电极用于通过 DPV 同时测定 DA 和 UA。结果表明，该电极对 DA 和 UA 的催化电氧化非常有效，导致两种化合物的峰分辨率显着提高（~350 mV）。该电极用于测定注射样品中的 DA。
