12th International Symposium on Bioluminescence & Chemiluminescence

Symposium abstracts:

Non trivial energy transfer processes in micellar solutions of phthalhydrazide and selected dyes

Hrbac, Jan, Lasovsky, Jan, Sichertova, Dana

Department of Inorganic and Physical Chemistry, tr. Svobody 26, 77146 Olomouc, Czech Republic
e-mail: hrbac@aix.upol.cz

The intramicellar sensitization of phthalhydrazide (PH) chemiluminescent oxidation by selected xanthene as well as two non-xanthene dyes has been investigated. Sodium hypochlorite and hydrogen peroxide - sodium hypochlorite initiated ISCL reactions are explainable using the classical idea of Förster type energy transfer (FRET). On the other hand if the alkaline copper sulphate - H₂O₂ system is used, anomally high ISCL intensities are observed, indicating the change in energy transfer mechanism. The primary emitter in PH chemiluminescence is the triplet state of phthalate. Its low phosphorescence quantum yield is responsible for low critical Förster distances, ca 2-5 times lower than micellar diameters. In hypochlorite initiated ISCL, the competing dark reactions of hypochlorite with dyes are observed. ISCL initiated by H₂O₂ - NaClO is noncomplicated FRET case and a model has been developed to interpret the results: 1. Efficient FRET occurs in micellar complexes with 1:1 micelle to dye ratio. 2. An equation describing the dependence of FRET efficiency on micellar diameter has been derived, based on the idea of random location of donor and acceptor molecules on the surface of a micelle.

This is a preprint of an article accepted for publication in Luminescence: Copyright 2001 John
Wiley & Sons, Ltd (Wiley website)