Spectrometric studies about some dyes — anionic surfactant interactions in aqueous solutions

This work presents some alternative analytical methods for anionic surfactant quantitative determination in aqueous solutions. Interactions of aqueous solutions of three dyes (Rhodamin B, Methyl violet and Fuchsin basic), concentrations 0.3×10−6 M, with two anionic surfactants in the concentration range of 10−5 M (sodium salt of naphthalene sulphonate formaldehyde condensates and melamine sulphonate formaldehyde condensates) have been investigated. Spectrometric measurements were performed on an UV–Vis spectrometer Hewlett Packard 8452A with diode array detection. From the UV–Vis spectra of individual and mixed dye–anionic surfactant aqueous solutions in various concentration ranges, specific changes in the chromophore microenvironment and in the intensity of absorbance is observed. These changes can be attributed to the chemical and structural characteristics of dyes and anionic surfactants, and could be exploited for analytical purposes.