Phase separation in an aqueous quaternary system

Edmond, Elizabeth; Ogston, A. G.

doi:10.1042/bj1170085

Cited by 22 publications

(6 citation statements)

References 5 publications

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“…Although it may be expected that salts will interact thermodynamically with Sephadex and will therefore affect the osmotic balance, we have found evidence (A. G. Ogston & J. D. Wells, unpublished work) that this effect is negligible for the purposes of osmotic pressure measurement. Osmotic pressures of polyelectrolyte solutions will of course (as in other methods of colloid osmometry) be subject to the Gibbs-Donnan equilibrium of permeant ions (Edmond & Ogston, 1970).…”

Section: Explanation Of Platementioning

confidence: 99%

Osmometry with single Sephadex beads

Ogston

Wells

1970

Biochemical Journal

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1. The measurement of osmotic pressure by means of a single bead of Sephadex (Edmond, Farquhar, Dunstone & Ogston, 1968) has been made more precise by immobilizing the bead on a fine needle. The design, calibration and use of the osmometer are described. 2. The method is particularly suitable for measuring high osmotic pressures in solutions of high-molecular-weight solutes, which must not penetrate the Sephadex to a significant extent. 3. With Sephadex G-50 the limit of precision is about 1.5cmH(2)O and the lower limit of molecular weight for a solute of compact molecular form is about 10(5). 4. The time required for each equilibration is less than 10min. 5. An impaled bead can be stored in the dry state without affecting its calibration. 6. Measurements on a sample of polyvinyl alcohol, degree of polymerization stated as 1750+/-50, gave m(n) 43000+/-3000 and A(2) (6.0+/-0.24)x10(-4).

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Section: Explanation Of Platementioning

confidence: 99%

Osmometry with single Sephadex beads

Ogston

Wells

1970

Biochemical Journal

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“…In this work, however, we are concerned with dilute aqueous multisolute solutions which are well described by the osmotic virial expansion. [22][23] Our current understanding of aqueous polymer solutions is severely limited, in part, because of a lack of fundamental experimental data. This work reports new experimental measurements at 25 °C for binary and ternary aqueous solutions of eight nonionic water-soluble polymers: dextran, poly (vinylpyrrolidone), methoxypoly(ethylene glycol), poly(vinyl alcohol), methylcellulose, Ficoll, Aquaphase PPT, and Bermocoll E.…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic properties of dilute aqueous polymer solutions from low-angle laser-light-scattering measurements

Rathbone¹,

Haynes²,

Blanch³

et al. 1990

Macromolecules

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Weight-average molecular weights and osmotic second virial coefficients obtained from lowangle laser-light-scattering (LALLS) measurements are reported for binary aqueous solutions of eight nonionic polymers at 25 °C. For dilute ternary aqueous solutions containing two polymers, cross osmotic second virial coefficients were also obtained from LALLS measurements. Using the truncated osmotic virial expansion, we find that the calculated water-vapor pressures for aqueous solutions of Dextran T-70 are in reasonable agreement with previously reported experimental vapor-pressure data in the dilute (<10 wt %) polymer region. At higher polymer concentrations, calculated vapor pressures are too low, indicating a need to include higher coefficients in the virial expansion.

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“…Here we reproduce the osmotic virial expansion based thermodynamic model for ATPS to show that osmotic virial coefficients are also important parameters for designing ATPS processes. The osmotic virial expansion that is commonly used for ATPS was first proposed by Edmond and Ogston [70,71]. On this basis, Prausnitz and co-workers established a simple theoretical framework to predict phase separation of aqueous polymer solutions [72] and biomolecule partitioning in these phases [73].…”

Section: Aqueous Two-phase Separation Processmentioning

confidence: 99%