Study of the absorption spectra of pyrene complexed to paraquat in pentanol–sodium dodecylsulphate micelles

The UV and visible spectra of pyrene complexed to paraquat in aqueous sodium dodecylsulphate (SDS) solutions have been studied as a function of the SDS concentration and the amount of pentanol solubilized in SDS micelles. The results have been analysed in terms of a change in the volume of solubilization of the complex and a partitioning of pyrene into a more alcoholic environment inside the micelle. This has led to a self-consistent interpretation of the complexation constant between pyrene and paraquat solubilized in SDS micelles.