Proton nuclear magnetic resonance study of the solubilization site of bromopyrogallol red in aqueous cationic/nonionic mixed micellar solutions

The solubilization site of bromopyrogallol red (BPR) in cetyltrimethylammonium bromide (CTAB)/Triton X-100(TNX) mixed micellar solutions was studied by the pulsed FT NMR technique. The changes in the chemical shifts of the individual groups of protons in the two surfactant molecules indicated that BPR was localized near the ammonium head group of CTAB and the benzene ring of TNX. Diluting the mixed micellar solution made BPR move a little toward the outer portion of the micelle while increasing the mole fraction of TNX made BPR move a little toward the inner portion of the micelle. (C) 1998 Elsevier Science B.V. All rights reserved.