Fluorescence and absorption spectral study of the interaction between cetylpyridinium and 2-naphtholate ions in aqueous solution

Abstract

Absorption spectral studies on aqueous solutions of cetylpyridinium chloride and sodium 2-naphtholate indicate the formation of cetylpyridinium naphtholate complexes. The complex is shown to be non-fluorescent, and the main cause for the decrease in 2-naphtholate fluorescence intensities with increasing cetylpyridinium concentrations below the critical micelle concentration of the surfactant involves complex formation. At higher surfactant concentrations, quenching of fluorescence of 2-naphtholate ions is also suggested to occur via a dynamic interaction between these ions and cetylpyridinium micelles.