State Key Laboratory for Physical Chemistry of Solid Surfaces, and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University , Xiamen, Fujian 361005, PR China.
CNRS UMR 8640 "PASTEUR", Sorbonne Universités - UPMC Univ Paris 06, Ecole Normale Supérieure - PSL Research University , Département de Chimie, 24 rue Lhomond, Paris 75005, France.
Anal Chem. 2016 Sep 6;88(17):8535-41. doi: 10.1021/acs.analchem.6b01454. Epub 2016 Aug 16.
The individual electrochemical anodic responses of dopamine (DA), epinephrine (EP), and pyrocatechol (CT) were investigated at arrays of recessed gold disk-microelectrodes arrays (MEAs) covered by a gold plane electrode and compared to those of their binary mixture (CT and EP) when the top-plane electrode was operated as a bipolar electrode or as a collector. The interferent species (EP) displays a chemically irreversible wave over the same potential range as the chemically reversible ones of DA or CT. As expected, in the generator-collector (GC) mode, EP did not contribute to the redox cycling amplification that occurred only for DA or CT. Conversely, in the bipolar mode, the presence of EP drastically increased the bipolar redox cycling efficiency of DA and CT. This evidenced that the chemically irreversible oxidation of EP at the anodic poles of the top plane floating electrode provided additional electron fluxes that were used to more efficiently reduce the oxidized DA or CT species at the cathodic poles. This suggests an easy experimental strategy for enhancing the bipolar efficiency of MEAs up to reach a performance identical to that achieved when the same MEAs are operated in a GC mode.
研究了在被金平面电极覆盖的凹陷金盘微电极阵列（MEA）阵列上，多巴胺（DA）、肾上腺素（EP）和邻苯二酚（CT）的个体电化学阳极响应，并将其与二元混合物（CT 和 EP）的响应进行了比较，当时顶平面电极作为双极电极或集电极运行。干扰物质（EP）在与 DA 或 CT 的化学可逆波相同的电位范围内显示出化学不可逆波。如预期的那样，在发生器-收集器（GC）模式下，EP 不会贡献仅发生在 DA 或 CT 上的氧化还原循环放大。相反，在双极模式下，EP 的化学不可逆氧化极大地提高了 DA 和 CT 的双极氧化还原循环效率。这表明，在顶部平面浮动电极的阳极上，EP 的化学不可逆氧化提供了额外的电子流，这些电子流可用于更有效地还原在阴极上氧化的 DA 或 CT 物质。这为增强 MEA 的双极效率提供了一种简单的实验策略，以达到与在 GC 模式下运行相同 MEA 时相同的性能。
