LAUSR

Abstract Interactions of oppositely charged dye (eosin yellow) and surfactant (Cetyltrimethylammonium bromide) were investigated using conductometric and spectrophotometric studies. The conductometric investigations showed a negligible change in critical micellar concentration of Cetyltrimethylammonium bromide at the point of the ion pair formation which was found to be 1 × 10−3 M. Spectroscopic studies revealed the formation of ion pair by a bathochromic shift of 10 nm in the original spectra by using yellow (517 nm) after the addition of cetyltrimethylammonium bromide (527 nm). The investigations were further confirmed the phenomenon by monitoring the effect of electrolyte, and calculating the values of thermodynamic parameters. Furthermore, the metal effect on dye and in dye-surfactant ion pair was studied and the noticeable change on the interactions were found. At the terminal part of the study the selectivity of dye-surfactant ion pair was observed. The system was found to be selective towards the eosin yellow among studied dyes.