Matching Effects in the Interaction of Ionic Surfactants with Fluorescent Reagents in Micellar Solutions of Triton X-100

The influence of cationic and anionic surfactant solutions on the character of the fluorescence spectra of reagents of different charge and hydrophobicity in aqueous solutions of nonionic surfactant Triton X-100 has been studied. An increase in the fluorescence intensity and a shift in the position of the fluorescence maximum with increasing hydrophobicity of reagents and ionic surfactants have been shown. The analytical signal of the surfactant is further amplified in the proximity of the charge values of the reagent and the counterion of the surfactant. The non-monotonic nature of the hydrophobicity effect of cationic surfactants on their analytical signal in the system has been shown. The observed effects are explained by the realization of charge and hydrophobic matching in the interaction of surfactants with the fluorescent reagents. The obtained effects are significant in the design of fluorescent systems for the determination and study of surfactant micelles. Conditions for detecting the content of cetylpyridinium chloride by reaction with eosin Y and sodium tetradecyl sulfate by reaction with rhodamine 6G in the presence of Triton X-100 were proposed. The methods have been tested in detecting the content of the ionic surfactants in pharmaceuticals.