Duran Boris, Brocenschi Ricardo F, France Marion, Galligan James J, Swain Greg M
Facultad de Química, Departamento de Farmacia, Pontificia Universidad Católica de Chile, Santiago, C.P. 7820436, Chile.
Analyst. 2014 Jun 21;139(12):3160-6. doi: 10.1039/c4an00506f. Epub 2014 May 7.
The electrochemical pretreatment of diamond microelectrodes was investigated for the purpose of learning how an anodic, cathodic or a combined anodic + cathodic polarization affects the charge-transfer kinetics for two surface-sensitive redox systems: ferri/ferrocyanide and serotonin (5-hydroxytryptamine, 5-HT). The pretreatments were performed in 0.5 mol L(-1) H2SO4. The anodic pretreatment was performed galvanically for 30 s at 250 mA cm(-2). The cathodic pretreatment was performed for 180 s at -250 mA cm(-2). The combined pretreatment involved application of the anodic step first followed by the cathodic step. The results clearly demonstrate that the best performance for both redox systems is obtained after the cathodic polarization, which presumably activates the electrode by cleaning the surface and removing site-blocking surface carbon-oxygen functionalities. The cathodic pretreatment was found to be effective at activating a fouled microelectrode in situ. This observation has important implication for the measurement of 5-HT in the bowel.
为了了解阳极、阴极或阳极+阴极联合极化如何影响两种表面敏感氧化还原体系（铁氰化铁/亚铁氰化铁和血清素（5-羟色胺，5-HT））的电荷转移动力学，对金刚石微电极的电化学预处理进行了研究。预处理在0.5 mol L(-1) H2SO4中进行。阳极预处理在250 mA cm(-2)下恒电流进行30 s。阴极预处理在-250 mA cm(-2)下进行180 s。联合预处理包括先进行阳极步骤，然后进行阴极步骤。结果清楚地表明，两种氧化还原体系在阴极极化后表现最佳，这可能是通过清洁表面和去除阻碍位点的表面碳氧官能团来激活电极。发现阴极预处理对于原位激活污染的微电极是有效的。这一观察结果对于肠道中5-HT的测量具有重要意义。
