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.
A method for the simultaneous determination of benzodiazepines in binary mixtures is proposed, based on the acid hydrolysis of benzodiazepines to benzophenones and the spectrophotometric determination of the latter in the presence of Nemol K 1030, a non-ionic surfactant condensate of ethylene oxide with nonylphenol. The experimental conditions for the hydrolysis of several benzodiazepines in sealed Pyrex tubes were determined. The addition of Nemol K 1030 to acidic solutions of benzophenones modified the positions of the absorption bands and made possible the simultaneous analysis of binary mixtures of benzodiazepines.
In the present paper, the possible analytical applications of two topological models, the DARC model and the group contribution model, are discussed. Both models are applied to obtain calibration laws, which relate UV and IR characteristics with the chemical structure of ethylene oxide condensates.The group contribution model is also applied to determine the contribution of each part of the different compounds involved in a chemical interaction process, having established the sensitization parameters of benzodiazepines and anionic surfactants from the micellar enhancement fluorescence. KEY WORDS Topological description of molecules Infrared and ultraviolet spectroscopy Surfactants Benzodiazepines Interaction processes 0886-9383/88/060193-15$07.50
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