Flow Equations and Frames of Reference for Isothermal Diffusion in Liquids

Kirkwood, John G.; Baldwin, Robert L.; Dunlop, Peter J.; Gosting, Louis J.; Kegeles, Gerson

doi:10.1063/1.1731433

Cited by 190 publications

(105 citation statements)

References 26 publications

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“…We can introduce the fluxes, (J i ) 0 ) J i -(C i /C 0 )J 0 , taken with respect to the solvent frame of reference, where C i (with i ) 0,..., N) is the molar concentration of component i. 3,21,34,35 If we insert (J i ) 0 into eq 1, we obtain…”

Section: Thermodynamic Driving Forces For Diffusionmentioning

confidence: 99%

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: Thermodynamic Driving Forces For Diffusionmentioning

confidence: 99%

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

Annunziata

2008

J. Phys. Chem. B

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“…24 Both J i and D ij depend on the reference frame (see below). 25,26 Due to the lack of data, diffusion in multicomponent systems has usually been approximated by neglecting cross-diffusion terms. However, this approximation can lead to inaccurate descriptions of transport processes.…”

Section: Introductionmentioning

confidence: 99%

Quaternary Diffusion Coefficients in a Protein−Polymer−Salt−Water System Determined by Rayleigh Interferometry

et al. 2009

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We have experimentally investigated multicomponent diffusion in a protein-polymer-salt-water quaternary system. Specifically, we have measured the nine multicomponent diffusion coefficients, D ij , for the lysozyme-poly(ethylene glycol)-NaCl-water system at pH 4.5 and 25°C using precision Rayleigh interferometry. Lysozyme is a model protein for protein-crystallization and enzymology studies. We find that the protein diffusion coefficient, D 11 , decreases as polymer concentration increases at a given salt concentration. This behavior can be quantitatively related to the corresponding increase in fluid viscosity only at low polymer concentration. However, at high polymer concentration (250 g/L), protein diffusion is enhanced compared to the corresponding viscosity prediction. We also find that a protein concentration gradient induces salt diffusion from high to low protein concentration. This effect increases in the presence of poly(ethylene glycol). Finally, we have evaluated systematic errors associated with measurements of protein diffusion coefficients by dynamic light scattering. This work overall helps characterize protein diffusion in crowded environments and may provide guidance for further theoretical developments in the field of protein crystallization and protein diffusion in such crowded systems, such as the cytoplasm of living cells.

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“…15 For isothermal diffusion, the matrix form of Fick's first law in this frame in one dimension is Here, the C i are molar concentrations and the (D ij ) V are volumefixed diffusion coefficients.…”

Section: Introductionmentioning

confidence: 99%

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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Flow Equations and Frames of Reference for Isothermal Diffusion in Liquids

Cited by 190 publications

References 26 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

Quaternary Diffusion Coefficients in a Protein−Polymer−Salt−Water System Determined by Rayleigh Interferometry

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

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