Zu Y, Bard A J
Department of Chemistry and Biochemistry, The University of Texas at Austin, 78712, USA.
Anal Chem. 2001 Aug 15;73(16):3960-4. doi: 10.1021/ac010230b.
We describe the effect of electrode surface hydrophobicity on the electrochemical behavior and electrogenerated chemiluminescence (ECL) of Ru(bpy)3(2+) (bpy = 2,2'-bipyridyl)/tripropylamine (TPrA) system. Gold and platinum electrodes were modified with different thiol monolayers. The hydrophobicity of the electrode surfaces changed with different terminal groups of the thiol molecules. The oxidation rate of TPrA was found to be much larger at the modified electrode with a more hydrophobic surface. The adsorption of neutral TPrA species on this kind of surface was assumed to contribute to the faster anodic kinetics. Due to the rapid generation of the highly reducing radical, TPrA., ECL intensity increased significantly at more hydrophobic electrodes. This electrode surface effect in the ECL analytical system allows one to improve the detection sensitivity at low concentrations of Ru(bpy)3(2+). The surfactant effect on the ECL process was also examined and discussed based on the change of electrode hydrophobicity by the adsorption of surfactant species.
我们描述了电极表面疏水性对Ru(bpy)3(2+)（bpy = 2,2'-联吡啶）/三丙胺（TPrA）体系的电化学行为和电致化学发光（ECL）的影响。金电极和铂电极用不同的硫醇单分子层进行了修饰。电极表面的疏水性随硫醇分子不同的端基而变化。发现在表面疏水性更强的修饰电极上，TPrA的氧化速率要大得多。中性TPrA物种在这种表面上的吸附被认为有助于更快的阳极动力学。由于高还原性自由基TPrA·的快速生成，在疏水性更强的电极上ECL强度显著增加。ECL分析体系中的这种电极表面效应能够提高在低浓度Ru(bpy)3(2+)时的检测灵敏度。基于表面活性剂物种吸附导致的电极疏水性变化，还对表面活性剂对ECL过程的影响进行了考察和讨论。
