Self-quenching in the electrochemiluminescence of Ru(bpy)32+ using ascorbic acid as co-reactant
✍ Scribed by Fumiki Takahashi; Jiye Jin
- Book ID
- 102760776
- Publisher
- John Wiley and Sons
- Year
- 2008
- Tongue
- English
- Weight
- 693 KB
- Volume
- 23
- Category
- Article
- ISSN
- 1522-7235
- DOI
- 10.1002/bio.1019
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✦ Synopsis
In this study, electrochemiluminescence (ECL) of Ru(bpy) 3 2+ (bpy = 2,2′-bipyridyl) using ascorbic acid (H 2 A) as co-reactant was investigated in an aqueous solution. When H 2 A was co-existent in a Ru(bpy) 3 2+ -containing buffer solution, ECL peaks were observed at a potential corresponding to the oxidation of Ru(bpy) 3 2+ , and the intensity was proportional to H 2 A concentration at lower concentration levels. The formation of the excited state *Ru(bpy) 3 2+ was confirmed to result from the co-reaction between Ru(bpy) 3 3+ and the intermediate of ascorbate anion radical (A -•), which showed the maximum ECL at pH = 8.8. It is our first finding that the ECL intensity would be quenched significantly when the concentration of H 2 A was relatively higher, or upon ultrasonic irradiation. In most instances, quenching is observed with four-fold excess of H 2 A over Ru(bpy) 3
2+
. The diffusional self-quenching scheme as well as the possible reaction pathways involved in the Ru(bpy) 3 2+ -H 2 A ECL system are discussed in this study.