Abstract
With reported values ranging from about 3 to 16, the aggregation number of aqueous sodium cholate micelles is not well established. To provide new information on the aggregation of a bile salt, Taylor dispersion is used to measure the binary mutual diffusion coefficientD of aqueous sodium cholate at concentrations from 0.001 to 0.100 mol-dm-3 at 25°C. The results are compared with calculatedD values based on the association equilibrium nCholate- + βnNa+ ⇋ (NaβCholate) (β-1)nn wheren is the aggregation number and β is the degree of sodium counterion binding. Fitting the association model to the diffusion data givesn = 3.9±0.6 and β = 0.21 ±0.08. In contrast to the drop inD with increasing concentration of sodium cholate, the diffusion coefficients of sodium dodecylsulfate and other long-chain ionic surfactants increase above the critical micelle region. The ent diffusion behavior of the surfactants is related to changes in the driving forces and mobilities caused by ion association.
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References
J. M. Beckerdite and E. T. Adams,Biophys. Chem. 21, 103 (1985).
D. Attwood and A. T. Florence,Surfactant Systems, Their Chemistry, Pharmacy and Biology (Chapman and Hall, London, 1983), p. 185.
J. M. Roe and B. W. Barry,J. Colloid Interface Sci. 107, 398 (1985).
P. Mukerjee and J. R. Cardinal,J. Pharm. Sci. 65, 882 (1976).
A. Coello, F. Meijide, E. R. Núñez, and J. V. Tato,J. Phys. Chem. 97, 10186 (1993).
M. C. Carey,Sterols and Bile Acids, H. Danielsson and J. Sjõvall, eds. (Elsevier, Amsterdam, 1985), Chap. 13.
W. B. Smith and G. D. Barnard,Can. J. Chem. 59, 1602 (1981).
M. Vadnere and S. Lindenbaum,J. Pharm. Sci. 71, 875 (1982).
B. Lindman, K. Kamenka, H. Fabre, J. Ulmius, and T. Wieloch,J. Colloid Interface Sci. 73, 556 (1980).
K. Fontell,Kolloid Z. Z. Polym. 244, 253 (1971).
J. Zakrzewska, V. Markovic, D. Vucelic, L. Feigin, A. Dembro, and L. Mogilevsky,J. Phys. Chem. 94, 5078 (1990).
J. P. Kratohvil,Hepatology 4, 85S (1984).
B. Lindman, N. Kamenka, and B. Brun,J. Colloid Interface Sci. 56, 328 (1976).
R. A. Robinson and R. H. Stokes,Electrolyte Solutions, 2nd edn., (Academic, New York, 1959).
D. G. Leaist and H. Lü,J. Phys. Chem. 94, 8741 (1990).
D. G. Leaist,Can. J. Chem. 66, 1129 (1988).
P. Mukerjee and K. J. Mysels,Critical Micelle Concentrations of Aqueous Surfactant Solutions, Nat. Stand. Ref. Data Ser. (Natl. Bur. Stand. (U.S.), Washington, 1971).
Z. Deng and D. G. Leaist,Can. J. Chem. 69, 1548 (1991).
D. G. Leaist,J. Chem. Soc, Faraday Trans. 76, 597 (1991).
J. P. Kratohvil, W. P. Hsu, M. A. Jacobs, T. M. Aminabhavi, and Y. Mukunoki,Colloid Polym. Sci. 261, 781 (1983).
D. G. Leaist,J. Colloid Interface Sci. 111, 230 (1986).
D. G. Leaist and L. Hao,J. Chem. Soc, Faraday Trans. 89, 2775 (1993).
H. S. Harned and B. B. Owens,Physical Chemistry of Electrolytic Solutions, 2nd edn., (Reinhold, New York, 1950), p. 38.
E. A. Guggenheim,Thermodynamics, 3rd edn., (North-Holland, Amsterdam, 1957), p. 355.
K. Juna and T. Sugano,Nippon Kagaku Zashi 90, 463 (1969).
R. Vochten and P. Joos,J. Chim. Phys.-Chim. Biol. 67, 1372 (1970).
Z. Deng, H. Lü and D. G. Leaist,J. Chem. Eng. Data 41, 214 (1996).
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Hao, L., Lu, R., Leaist, D.G. et al. Aggregation number of aqueous sodium cholate micelles from mutual diffusion measurements. J Solution Chem 26, 113–125 (1997). https://doi.org/10.1007/BF02767916
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DOI: https://doi.org/10.1007/BF02767916