FLUORESCENCE QUENCHING OF INDOLIC COMPOUNDS IN REVERSE MICELLES OF AOT

Abstract— The fluorescence properties of indole, 1,2‐dimethylindole and tryptophan have been determined in sodium bis(2‐ethylhexyl)sulfosuccinate inverse micelles in heptane. Fluorescence quenching studies were done using CCl4 and acrylamide as quenchers localized in the organic and micellar pseudophase respectively. The Stern‐Volmer plots show departure from linearity and are dependent on the emission wavelength. The results were interpreted using a three pseudophases model. 1,2‐Dimethylindole is predominantly solubilized in the n‐heptane; however a small interaction with the micelles is apparent at high detergent concentration. Indole is distributed between the organic and the interfacial microphase with a partition constant of 34 ± 3, independent of the water content. Tryptophan is entirely localized at the interface. However the quenching experiments show that tryptophan molecules are not uniformly distributed in the interfacial pseudophase. Copyright © 1990, Wiley Blackwell. All rights reserved