Influence of anionic surfactants on the sensitisation of the fluorimetric determination of fenproporex

Abstract

The effect of the addition of anionic surfactants on the fluorescence of fenproporex has been studied. A micellar enhancement factor of 2.6 was found in the presence of 0.5% of sodium dodecyl sulphate, which provides a detection limit in the fluorimetric determination of this amphetamine of 0.8 p.p.m. The fact that no significant increase in the molar absorptivity at 260 nm was obtained indicates that the fluorescence enhancement is due to an improvement of the fenproporex quantum yield in the environment of the heteromicelles formed with the surfactant molecules. An estimation of the sensitisation parameters for the different moieties of the surfactant molecules was obtained from the study of the fluorescence enhancement of fenproporex in different media using a topological description of each surfactant considered.