EurekaMag.com logo
+ Site Statistics
References:
52,725,316
Abstracts:
28,411,598
+ Search Articles
+ Subscribe to Site Feeds
EurekaMag Most Shared ContentMost Shared
EurekaMag PDF Full Text ContentPDF Full Text
+ PDF Full Text
Request PDF Full TextRequest PDF Full Text
+ Follow Us
Follow on FacebookFollow on Facebook
Follow on TwitterFollow on Twitter
Follow on Google+Follow on Google+
Follow on LinkedInFollow on LinkedIn

+ Translate

Electrostatic and electrokinetic potentials in 2 polymer aqueous phase systems


Journal of Colloid & Interface Science 102(1): 1-13
Electrostatic and electrokinetic potentials in 2 polymer aqueous phase systems
Two polymer aqueous phase systems have proven useful as partition media for biological cells, the partition coefficients obtained being dependent on cell surface properties. One such property appears to be the surface charge density of cells which prompted this detalied examination of electrostatic potential distributions in dextran/poly(ethylene glycol) 2 phase systems. The partition coefficients of potassium sulfate and potassium chloride in the phase systems were measured and correlated with Donnan potential difference between the phases measured with salt bridges to reversible electrodes. Thermodynamic predictions of the relationship between the 2 measured quantities were confirmed. The preference of sulfate for the dextran-rich bottom phase, which linearly increases with increasing poly(ethylene glycol) (PEG) concentration, is due to the greater exclusion of sulfate by PEG than by dextran, as indicated by equilibrium dialysis of the polymer against different salt concentrations. Electrokinetic studies of droplets of one phase suspended in the other phase revealed relatively large electrophoretic droplet mobilities which increased linearly with the drop diameter and supralinearly with the sulfate concentration. The sign of the mobility depended on the phase the droplet originated from, but the implied surface charge sign was opposite to that anticipated from the difference in potential between the bulk phases. Assuming the mobility and zeta potential are of the same sign, the simplest potential profile which is consistent with these observations is one in which a dipole potential is present at the phase boundary oriented in such a way as to locally reverse the potential gradient. Levine's partial theory for the electrophoresis of systems of this type was tested and found to be consistent with our results. The correlations obtained suggest that the magnitude of the dipole potential is related to the anion partition coefficient in these systems.


Accession: 005349976



Related references

Electrokinetic demixing of aqueous two-phase polymer/salt systems. Electrophoresis 26(1): 10-17, 2004

Electrokinetic demixing of two phase aqueous polymer systems i. separation rates of polyethylene glycol dextran mixtures. Separation Science and Technology 25(9-10): 985-996, 1990

Electrokinetic demixing of two phase aqueous polymer systems ii. separation rates of polyethylene glycol maltodextrin mixtures. Separation Science and Technology 26(2): 257-268, 1991

Cell partitioning in two-polymer aqueous phase systems and cell electrophoresis in aqueous polymer solutions: Human and rat young and old red blood cells. Biochimica et Biophysica Acta 1194(1): 131-137, 1994

Cell partitioning in two-polymer aqueous phase systems and cell electrophoresis in aqueous polymer solutions. Human and rat young and old red blood cells. Biochimica et Biophysica Acta 1194(1): 131-137, 1994

Cell partitioning in two-polymer aqueous phase systems and cell electrophoresis in aqueous polymer solutions. Red blood cells from different species. Journal of Chromatography. A 668(1): 185-190, 1994

Electrostatic interactions, phase separation behaviour and partitioning of proteins in polyelectrolyte based aqueous two-phase systems. Indian Journal of Biotechnology 1(1): 87-95, January, 2002

"On the Collander equation": protein partitioning in polymer/polymer aqueous two-phase systems. Journal of Chromatography. A 1190(1-2): 39-43, 2008

DeltaG(CH2) as solvent descriptor in polymer/polymer aqueous two-phase systems. Journal of Chromatography. A 1185(1): 85-92, 2008

Delta G(CH2) as solvent descriptor in polymer/polymer aqueous two-phase systems. Journal of Chromatography A 1185(1): 85-92, 2008