Sensitized lanthanide luminescence in AOT reversed micelles - Purine compounds as energy donor

Abstract

Sensitized lanthanide luminescence by purine compounds in AOT reversed micelles has been studied. A significant enhancement of sensitized room temperature luminescence has been observed using lanthanide Tb3+ as energy acceptor in AOT reversed micelles at low AOT concentration and W value, and weak Tb3+ emission has been observed in CTAB reversed micelles. The results indicate that Tb3+ ions are strongly bound to the sulfonate group of the AOT surfactant. Parameters including the concentration of AOT, solubilized water as well as acceptor concentration that may influence the sensitized lanthanide luminescence have been examined. The characteristics of luminescence and lifetimes of Tb3+ were used to elucidate the factors that affected sensitized luminescence. The results shaw that Tb3+ emission is quenched by the high frequency OH vibrations of the surrounding water molecules, the loss of Tb3+ emission in high AOT concentration and W value suggests that the Tb3+ cation retains water in its coordination sites. The quenching process is static quenching. The low AOT concentration and W value should be reconmmended for obtaining high sensitivity in analytical application. The detection limits for purine and its deriviations are between 8.0 x 10(-9)similar to 8.0 x 10(-7) mol.dm(-3).