A graphene platform electrode (GPE) was prepared directly by transferring chemical vapor deposited (CVD) graphene films from Cu foils to polyethylene terephthalate substrates with the aid of polymethyl-methacrylate, a distinct advantage over previously developed methods. L-Cysteine (L-Cys) was polymerized on the GPE by using a one-step electrodeposition technique to form a poly-L-Cys/GPE. As a negatively charged polymer, the poly-L-Cys could adsorb positively charged dopamine (DA) and repel negatively charged ascorbic acid (AA) under optimum conditions. As a result, a novel electrochemical sensor for the simultaneous determination of DA and AA was developed. The electrochemical behaviors of DA and AA were investigated by cyclic voltammetry. Differential pulse voltammetry was used for determining DA and AA in their mixture, where the separation between oxidation peak potentials of DA and AA was about 163 mV. The broad linear responses to DA and AA were determined by chronoamperometry, which were 0.2 to 423 μM and 1 to 580 μM with detection limits (S/N = 3) of 0.0531 μM and 0.2031 μM, respectively. In addition, the as-obtained sensor delivered good stability as well as high resistance to interference, and was successfully utilized in determining real samples. Consequently, the poly-L-Cys/GPE could be considered as a new promising DA and AA sensor, strongly indicating that CVD graphene could be used successfully as a material in electrochemistry.

中文翻译：

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CVD石墨烯掺入聚合升-半胱氨酸作为电化学感测平台的多巴胺和抗坏血酸同时测定

石墨烯平台电极（GPE）是通过在聚甲基丙烯酸甲酯的帮助下将化学气相沉积（CVD）石墨烯薄膜从铜箔转移到聚对苯二甲酸乙二酯基材上而直接制备的，这是以前开发方法的明显优势。通过使用一步电沉积技术，将L-半胱氨酸（L -Cys）在GPE上聚合，以形成聚L -Cys / GPE。作为带负电荷的聚合物，聚-L-Cys可以在最佳条件下吸附带正电荷的多巴胺（DA），并排斥带负电荷的抗坏血酸（AA）。结果，开发了用于同时测定DA和AA的新型电化学传感器。用循环伏安法研究了DA和AA的电化学行为。使用差分脉冲伏安法测定混合物中的DA和AA，其中DA和AA的氧化峰电位之间的间隔约为163 mV。通过计时安培法测定对DA和AA的宽线性响应，分别为0.2至423μM和1至580μM，检测极限（S / N = 3）分别为0.0531μM和0.2031μM。另外，所获得的传感器具有良好的稳定性以及高抗干扰性，并已成功用于确定真实样品中。所以，L -Cys / GPE可以被认为是一种新的有前途的DA和AA传感器，强烈表明CVD石墨烯可以成功地用作电化学材料。