<b>Isothermal Diffusion Measurements on the System H<sub>2</sub>O-Glycine-KCl at 25°; Tests of the Onsager Reciprocal Relation</b>

Woolf, L. A.; Miller, Donald G.; Gosting, Louis J.

doi:10.1021/ja00862a001

Cited by 97 publications

(103 citation statements)

References 11 publications

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“…The frictional coefficients satisfy the conditions ∑ j ) 0 N C j ij ) 0 and ij ) ji with i + j. 35 Equation 18 is equivalent to resistancebased equations previously reported by Onsager 26 and to the Stefan-Maxwell equations. 44 Contrary to (L ik ) r , ij are frame independent and have a direct physical interpretation in terms of friction between the system components.…”

Section: Frictional-coefficient Formulation Of Diffusionmentioning

confidence: 99%

“…These coefficients obey the Onsager reciprocal relations: (L ij ) 0 ) (L ji ) 0 with i + j. 35,36 We can also introduce the fluxes, (…”

Section: Thermodynamic Driving Forces For Diffusionmentioning

confidence: 99%

“…, taken with respect to the center of volume of the system, 3,35 where V j i (with i ) 0,..., N) is the partial molar volume of component i. If we insert (J i ) V into eq 1 with…”

Section: Thermodynamic Driving Forces For Diffusionmentioning

confidence: 99%

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On the Role of Solute Solvation and Excluded-Volume Interactions in Coupled Diffusion

Annunziata

2008

J. Phys. Chem. B

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Coupled diffusion is observed in multicomponent liquid mixtures in which strong thermodynamic interactions occur. This phenomenon is described by cross terms in the matrix of multicomponent diffusion coefficients. This paper reports a theoretical analysis on the relative role of thermodynamic factors and Onsager crosscoefficients on cross-diffusion coefficients relevant to ternary mixtures containing macromolecules or colloidal particles in the presence of salting-out conditions. A new model based on frictional coefficients between solvated solutes is reported. This model predicts that the Onsager cross-coefficient is negative and contributes significantly to cross-diffusion coefficients even at infinite dilution for solutes with a large difference in size. These predictions are consistent with recent experimental results. The role of preferential solvation and excludedvolume interactions on the thermodynamic factors are also examined. Excluded-volume interactions are introduced through the use of the McMillan-Mayer thermodynamic framework after emphasizing some important aspects of diffusion reference frames and thermodynamic driving forces. Finally, new expressions for cross-diffusion coefficients are proposed.

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Section: Frictional-coefficient Formulation Of Diffusionmentioning

confidence: 99%

“…These coefficients obey the Onsager reciprocal relations: (L ij ) 0 ) (L ji ) 0 with i + j. 35,36 We can also introduce the fluxes, (…”

Section: Thermodynamic Driving Forces For Diffusionmentioning

confidence: 99%

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On the Role of Solute Solvation and Excluded-Volume Interactions in Coupled Diffusion

Annunziata

2008

J. Phys. Chem. B

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“…[25][26][27][28][29] The thermodynamics of macromolecule-salt aqueous mixtures is commonly described using molality-based chemical potential derivatives: The preferential interaction coefficient, Γ 12 , is defined by: 7,14 We now show how to relate Γ 12 to the solvent-frame diffusion coefficients. We can first solve eq 5a-d with respect to (L 12 This implies that µ 11 (m) ) 1/m 1 is an excellent approximation for relatively low macromolecule concentrations (≈10 mg/mL).…”

Section: Theorymentioning

confidence: 99%

Determination of Preferential Interaction Parameters by Multicomponent Diffusion. Applications to Poly(ethylene glycol)−Salt−Water Ternary Mixtures

2008

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Poly(ethylene glycol) (PEG) is a hydrophilic nonionic polymer used in many biochemical and pharmaceutical applications. We report the four diffusion coefficients for the PEG-KCl-water ternary system at 25°C using precision Rayleigh interferometry. Here, the molecular weight of PEG is 20 kg mol -1 , which is comparable to that of proteins. The four diffusion coefficients are examined and used to determine thermodynamic preferential interaction coefficients. We find that the PEG preferential hydration in the presence of KCl is 1 order of magnitude larger than that previously obtained under the same conditions for lysozyme, a protein of similar molecular weight. In correspondence, the coupled diffusion in the PEG case was greater than that observed in the lysozyme case. We attribute this difference to the greater exposure of polymer coils to the surrounding fluid compared to that of globular compact proteins. Moreover, we observe that the PEG preferential hydration significantly decreases as salt concentration increases and attribute this behavior to the polymer collapse. Finally, we have also employed the equilibrium isopiestic method to validate the accuracy of the preferential interaction coefficients extracted from the diffusion coefficients. This experimental comparison represents an important contribution to the relation between diffusion and equilibrium thermodynamics.

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“…This has important implications on the pH dependence of protein solubility at constant salt concentration. It is generally expected (dS 1 /dC 2 ) ) -(µ 12 /µ 11 ) + (dµ 1 s /dC 2 )/µ 11 (17) …”

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confidence: 98%

The Effect of Salt on Protein Chemical Potential Determined by Ternary Diffusion in Aqueous Solutions

et al. 2005

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We use accurate thermodynamic derivatives extracted from high-precision measurements of the four volumefixed diffusion coefficients in ternary solutions of lysozyme chloride in aqueous NaCl, NH 4 Cl, and KCl at pH 4.5 and 25°C to (a) assess the relative contributions of the common-ion and nonideality effects to the protein chemical potential as a function of salt concentration, (b) compare the behavior of the protein chemical potential for the three salts, which we found to be consistent with the Hofmeister series, and (c) discuss our thermodynamic data in relation to the dependence of the protein solubility on salt concentration. The four diffusion coefficients are reported at 0.6 mM lysozyme chloride and 0.25, 0.5, 0.9, 1.2, and 1.5 M KCl and extend into the protein-supersaturated region. The chemical potential cross-derivatives are extracted from diffusion data using the Onsager reciprocal relation and the equality of molal cross-derivatives of solute chemical potentials. They are compared to those calculated previously from diffusion data for lysozyme in aqueous NaCl and NH 4 Cl. We estimate the effective charge on the diffusing lysozyme cation at the experimental concentrations. Our diffusion measurements on the three salts allowed us to analyze and interpret the four diffusion coefficients for charged proteins in the presence of 1:1 electrolytes. Our results may provide guidance to the understanding of protein crystallization.

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Isothermal Diffusion Measurements on the System H₂O-Glycine-KCl at 25°; Tests of the Onsager Reciprocal Relation

Cited by 97 publications

References 11 publications

On the Role of Solute Solvation and Excluded-Volume Interactions in Coupled Diffusion

On the Role of Solute Solvation and Excluded-Volume Interactions in Coupled Diffusion

Determination of Preferential Interaction Parameters by Multicomponent Diffusion. Applications to Poly(ethylene glycol)−Salt−Water Ternary Mixtures

The Effect of Salt on Protein Chemical Potential Determined by Ternary Diffusion in Aqueous Solutions

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Isothermal Diffusion Measurements on the System H2O-Glycine-KCl at 25°; Tests of the Onsager Reciprocal Relation

Cited by 97 publications

References 11 publications

On the Role of Solute Solvation and Excluded-Volume Interactions in Coupled Diffusion

On the Role of Solute Solvation and Excluded-Volume Interactions in Coupled Diffusion

Determination of Preferential Interaction Parameters by Multicomponent Diffusion. Applications to Poly(ethylene glycol)−Salt−Water Ternary Mixtures

The Effect of Salt on Protein Chemical Potential Determined by Ternary Diffusion in Aqueous Solutions

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Isothermal Diffusion Measurements on the System H₂O-Glycine-KCl at 25°; Tests of the Onsager Reciprocal Relation