| Abstract
| - We describe the quenching effects of phenolic compounds on the electrogenerated chemiluminescence (ECL)of the Ru(bpy)32+ (bpy = 2,2‘-bipyridine)/tri-n-propylamine (TPrA) system in aqueous solution. First, theemissions via different ECL routes were examined in the presence of 1,4-benzoquinone. It was found that theinterception of the ECL intermediate radicals by the quencher molecules significantly influenced the lightemission, especially when the direct coreactant oxidation played a predominant role in producing ECL. Themost efficient quenching was observed for the low-oxidation-potential (LOP) ECL at a low concentration ofTPrA (<5 mM). The Stern−Volmer constant (KSV) of the LOP ECL quenching could be as high as 1.3 × 106M-1, ∼700 times larger than that of the photoluminescence quenching. Other phenolic compounds, such asphenol, 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 forthe determination of these pharmaceutically and environmentally important molecules.
|
