Properties of aqueous solution of sodium glycocholate and a nonionic surfactant, and their mixtures

Abstract

The micellar properties of aqueous binary mixed solutions of sodium glycocholate, NaGC, and octa-oxyethylene glycol mono-n-decyl ether, C10Es, have been studied on the basis of surface tensions, the mean aggregation number and the polarity of the interior of the micelles. The mean aggregation number, measured by steady state quenching method, decreased with the increase of the mole fraction of NaGC in the mixed system. The polarity of the interior, estimated by the ratio of first and third vibronic peak in a monomeric pyrene fluorescence emission spectrum, suggested that the hydrophobicity ofintramicelles increased with the increase of the mole fraction of NaGCin the mixed system. These are considered to be caused by the differences in the chemical structure and the hydrophobic nature between NaGC and C10Es. The mean aggregation number and the polarity of the interior for each micelle near the CMC in lower total concentration of surfactants showed the tendency approaching those of pure micelle of the nonionic surfactant. This suggests that the ratio of NaGC in the initial micelles in the range of lower total concentration near the CMC is lower than that of the corresponding prepared mole fraction in the mixed system. This lower value was confirmed also from theoretical calculation of the ratio of NaGC at the CMC in the mixed micelle by regular solution treatment of Rubingh in the solution.

Surface Properties and Micellar Molecular Interaction in Binary Systems of a Biosurfactant Sodium Deoxycholate (NaDC) with Conventional Surfactants

“…The X 1 calculated by all these models increases with increases in a NaDC , but the proportion of NaDC in the mixed micelle is very small even at high a NaDC . This is consistent with the conclusions found in previous works [17,19,20]. Take NaDC/C 18 = EO 10 system for example, X 1 is 0.318 when a NaDC equals 0.95.…”

“…Earlier studies on the mixtures of bile salts and the other common surfactants have been carried out. These surfactants involve nonionic surfactants C 10 EO 8 [17], MEGA-10 [18], anionic surfactant sodium dodecyl sulfate SDS [19] and cationic surfactant cetyltrimethyl ammonium bromide CTAB [19,20]. From the results in the literature, the micellar molecular interaction parameter values (b) are between -5 and ?4.…”

“…Various theoretical models are available to interpret the formulation of mixed micelles [10][11][12][13][14][15][16]. Relative to the research in micelle structure of bile salts, the studies on mixed micelle formation of bile salts/conventional surfactants mixtures are very scarce [17][18][19][20][21]. Earlier studies on the mixtures of bile salts and the other common surfactants have been carried out.…”

Improved separation of integral membrane proteins by continuous elution electrophoresis with simultaneous detergent exchange: Application to the purification of the fusion protein of the human immunodeficiency virus type 1

“…The mixture was placed on ice for 1 h. The SDS/Triton mixed micelles thus formed were on the average less than half the size of a triton micelle alone [26][27][28].…”

Thermodynamic Studies of Sodium Dodecyl Sulfate–Sodium Dodecanoate Mixtures in Water

“…The instrument was calibrated using aqueous NaCl X NaL Å m NaL /m t , X NaDS Å m NaDS /m t [2] solutions at given osmolalities (22). The F accuracy is of the order of 2%.…”