|
12th International Symposium on Bioluminescence & Chemiluminescence |
Symposium abstracts:
Hua Cui, Guizheng Zou, Xiangqin Lin
Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, People’s Republic of China
Email: hcui@ustc.edu.cn; xqlin@ustc.edu.cn
The behavior of luminol electrochemluminescence (ECL) at a polycrystalline gold electrode at different applied potentials was studied in a thin layer cell under conventional cyclic voltammetric (CV) conditions. A potential-resolved electrochemiluminesecence (PRECL) curve, i.e. the curve of ECL intensity versus the applied potential, was obtained. It was found the ECL was related to the applied potentials and reaction conditions. At least Five ECL peaks were observed at 0.26 (ECL-1), 0.55 (ECL-2), 0.85 (ECL-3), 1.4 (ECL-4) and —0.4 V (ECL-5) (vs Ag), which was affected by O2, N2, pH of the solution, KCl concentration and potential scan ranges. It is believed that ECL-1 at 0.26 V is likely due to the direct electro-oxidation of luminol and ECL-2 at 0.55 V was caused by gold oxide formed on the electrode surface. ECL-1 and ECL-2 can be strongly enhanced by O2. The reason for the formation of ECL-3 is not clear. ECL-4 at 1.0 V and ECL-5 at —0.4 V seem to be related to fresh atomic oxygen [O], ClO- and [AuCl4]- formed at higher potentials and HO2- electrogenerated at negative potential. The results indicated that luminol ECL can be readily initiated by various oxygen-containing species electrogenerated at different applied potentials, leading to multi-channel light emission, which can not be observed in pulse-excited ECL. Luminol PRECL may provide a simple way to improve the selectivity for the detection of some compounds by use of different electrode potentials.
This
is a preprint of an article accepted for publication in Luminescence: Copyright
2001 John
Wiley & Sons, Ltd (Wiley website)