Abstract：
This work presents a significant investigation involving both electrochemical experiment and quantum chemical simulation approaches. The objective was to characterize the electrochemical detection of dopamine (DA). The detection was carried out using a modified carbon paste electrode (CPE) incorporating bentonite (Bent) and l-cysteine (CySH) (named as CySH/Bent/CPE). To understand and explain the oxidation mechanism of DA on the CySH/Bent modified electrode surface, the coupling of the two approaches were exploited. The CySH/Bent/CPE showed excellent electroactivity toward DA such as good sensibility, selectivity, stability, and regenerative ability. The developed sensor shows a dynamic linear range from 0.8 to 80 μM with a limit of detection and quantification of 0.5 μM and 1.5 μM, respectively. During the quantitative analysis of DA in presence of ascorbic acid (AA) and uric acid (UA) the electrochemical oxidation signals of AA, DA, and UA distinctly appear as three separate peaks. The potential differences between the peaks are 190 mv, 150 mv, and 340 mV for the AA-DA, DA-UA, and AA-UA oxidation pairs, respectively. These observations stem from square wave voltammetry (SWV) studies, along with the corresponding redox peak potential separations. The developed sensor is simple and accurate to monitor DA in human serum samples. On the other hand, CySH acts as an electrocatalyst on the CySH/Bent/CPE surface by increasing its active electron transfer sites, as suggested by the quantum chemical modeling with analytical results of Fukui. Furthermore, the voltammetric results obtained agree well with the theoretical calculations.
摘要：
这项工作提出了涉及电化学实验和量子化学模拟方法的重要研究。目的是表征多巴胺（DA）的电化学检测。使用结合有膨润土(Bent)和1-半胱氨酸(CySH)(命名为CySH/Bent/CPE)的改性碳糊电极(CPE)进行检测。了解和解释DA在CySH/Bent修饰电极表面的氧化机理,利用了两种方法的耦合。CySH/Bent/CPE对DA表现出优异的电活性，如良好的敏感性，选择性,稳定性,和再生能力。所开发的传感器显示出0.8至80μM的动态线性范围，检测和定量极限为0.5μM和1.5μM，分别。在抗坏血酸（AA）和尿酸（UA）存在下的DA的定量分析过程中，AA的电化学氧化信号，DA,和UA明显表现为三个独立的峰。峰之间的电位差为190mv,150mv,AA-DA为340mV，DA-UA,和AA-UA氧化对，分别。这些观察来自方波伏安法（SWV）研究，随着相应的氧化还原峰电位分离。所开发的传感器简单，准确地监测人血清样品中的DA。另一方面,CySH通过增加其活性电子转移位点而在CySH/Bent/CPE表面上充当电催化剂，正如具有福井分析结果的量子化学模型所建议的那样。此外，得到的伏安结果与理论计算吻合良好。
