Interaction of 8-hydroxypyrene-1,3,6-trisulphonate in alkyltrimethylammonium bromide (CnTAB) micellar medium

Interaction of 1-hydroxy-pyrene-3,6,8-trisulphonate (HPTS) has been investigated in well-characterized, monodispersed, micellar media of cationic surfactants of a homologous series having the general formula CnTAB and with trisodium citrate, employing absorption and fluorescence spectroscopy. The interaction of HPTS with cationic micelles depends on the hydrophobic chain length of the cationic surfactants. The binding constant of HPTS with CnTAB micelles decreases with decreasing n. Micelles have strong effect on the interaction of HPTS with trisodium citrate. Fluorescence of HPTS is quenched by citrate ion at the surface of the micelle and the rate of fluorescence quenching decreases with decreasing alkyl chain length of cationic surfactants.