Zheng Huzhi, Zu Yanbing
Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, PR China.
J Phys Chem B. 2005 Aug 25;109(33):16047-51. doi: 10.1021/jp052843o.
We describe the quenching effects of phenolic compounds on the electrogenerated chemiluminescence (ECL) of the Ru(bpy)3(2+) (bpy = 2,2'-bipyridine)/tri-n-propylamine (TPrA) system in aqueous solution. First, the emissions via different ECL routes were examined in the presence of 1,4-benzoquinone. It was found that the interception of the ECL intermediate radicals by the quencher molecules significantly influenced the light emission, especially when the direct coreactant oxidation played a predominant role in producing ECL. The most efficient quenching was observed for the low-oxidation-potential (LOP) ECL at a low concentration of TPrA (<5 mM). The Stern-Volmer constant (K(SV)) of the LOP ECL quenching could be as high as 1.3 x 10(6) M(-1), approximately 700 times larger than that of the photoluminescence quenching. Other phenolic compounds, such as phenol, hydroquinone, catechol, and dopamine, would be oxidized at the potential where the ECL was generated, and the benzoquinone-containing products exhibited ECL quenching effects similar to that of 1,4-benzoquinone. The highly efficient quenching of the LOP ECL by the phenolic compounds may provide a new approach for the determination of these pharmaceutically and environmentally important molecules.
我们描述了酚类化合物对水溶液中Ru(bpy)3(2+)（bpy = 2,2'-联吡啶）/三正丙胺（TPrA）体系的电化学发光（ECL）的猝灭效应。首先，在1,4-苯醌存在下研究了通过不同ECL途径的发射。发现猝灭剂分子对ECL中间自由基的拦截显著影响发光，特别是当直接共反应物氧化在产生ECL中起主要作用时。在低浓度TPrA（<5 mM）下，对低氧化电位（LOP）ECL观察到最有效的猝灭。LOP ECL猝灭的斯特恩-沃尔默常数（K(SV)）可高达1.3×10(6) M(-1)，约为光致发光猝灭常数的700倍。其他酚类化合物，如苯酚、对苯二酚、邻苯二酚和多巴胺，会在产生ECL的电位下被氧化，含苯醌的产物表现出与1,4-苯醌类似的ECL猝灭效应。酚类化合物对LOP ECL的高效猝灭可能为测定这些在药学和环境方面重要的分子提供一种新方法。
