Solute partitioning in polymer–salt ATPS: The Collander equation

Abstract

a b s t r a c tThe partition coefficients for several solutes (five nitrophenylated-monosaccharides and four proteins) were experimentally determined, at 23 • C, in three different tie-lines of two polymer-salt aqueous twophase systems (ATPS): UCON-K 2 HPO 4 and UCON-NaH 2 PO 4 . These partition coefficients together with others obtained from the literature for five dinitrophenylated-amino acids were used to investigate the suitability of the Collander equation to correlate partition coefficients in polymer-salt ATPS. This equation was first proposed to describe the linear correlation between partition coefficients of solutes in different water-organic solvent systems. More recently, it was proved that partition coefficients for several biomolecules in polymer-polymer ATPS can also be correlated with this equation. In this work, several correlations were tested: partition coefficients obtained for different tie-lines within the same system and also partition coefficients obtained from different systems. In both cases, a linear relation was observed, despite a less satisfactory correlation was found when different ATPS were compared. Overall, it was demonstrated that the Collander equation can be used to satisfactorily correlate solute partitioning in the studied polymer-salt ATPS.

Effect of salt additives on partition of nonionic solutes in aqueous PEG–sodium sulfate two-phase system

“…It was found to be valid for solutes of the same chemical nature, as it holds only if the relative intensities of all the solvent-solute interactions in the coexisting phases are changed similarly in the systems under comparison. Data reported in the literature [5,16,22,23] on the relative hydrophobicity of various ATPS measured by the free energy of transfer of a methylene group between the coexisting phases show that the relative hydrophobicity of ATPS formed by PEG and salt are close to that typical for organic solvent-water systems. It is likely that in ATPS with high salt additive concentrations some specific solute-solvent interactions may occur for certain solutes under study as the result of ion-dipole, ion-induced dipole, and dipole-induced dipole interactions, for example.…”

“…It implies that there are just two additive factors driving distribution of a solute between the coexisting phases, namely, the difference between the relative hydrophobicity of the phases and the difference between the solute-solvent polar interactions in the two phases. It was shown [22,23,29] that the partition coefficient of solute in both PEG-salt and two-polymer ATPS is described better as a sum of intensities of different solute-solvent interactions within the framework of the so-called Linear Solvation Energy Relationship (LSER) model developed by Abraham [30][31][32][33][34]. Future studies will investigate whether this approach would be useful for describing the mechanisms surrounding the effects of salt additives on partitioning of solutes in PEG-salt ATPS.…”

Phase diagrams, densities and refractive indexes of poly(ethylene oxide)+organic salts+water aqueous two-phase systems: Effect of temperature, anion and molar mass

“…Aqueous two-phase system (ATPSs) have been used for the extraction, separation and purification of solutes such as proteins [1], enzymes [2], amino acids [3], antibiotics [4], nucleic acids [5], ions [6][7][8][9], nanomaterials [10], and organic molecules [11][12][13].…”

Thermodynamic investigation of the ATPSs composed of some (aliphatic alcohol+sodium carbonate+water) ternary systems

“…ATPSs composed of (polymer + salt + water) ternary systems have been widely used for the partitioning and purification of proteins, human antibodies, enzymes, and other biological macromolecules [1][2][3][4][5][6][7]. Also, Greve and Kula [8] have used the alcohol-saltwater ATPSs to extract the salt from (polymer + salt + water) protein extraction systems to minimize the environmental pollution as well as to economize on the use of chemicals.…”