title: Cooperativity between various types of polar solute-solvent interactions in aqueous media.
abstract: Partition coefficients of seven low molecular weight compounds were measured in multiple aqueous two-phase systems (ATPSs) formed by pairs of different polymers. The ionic composition of each ATPS was varied to include 0.01M sodium phosphate buffer (NaPB), pH 7.4 and 0.1M Na2SO4, 0.15M NaCl, and 0.15M NaClO4 all in 0.01M NaPB, pH 7.4. The differences between the solvent features of the coexisting phases in all the ATPSs were estimated from partitioning of a homologous series of dinitrophenylated-amino acids and by the solvatochromic method. The solute-specific coefficients for the compounds examined were determined by the multiple linear regression analysis using the modified linear solvation energy relationship equation. It is established that the solute specific coefficients characterizing different types of the solute-water interactions (dipole-dipole, dipole-ion, and H-bonding) for a given solute change in the presence of different salt additives in the solute specific manner. It is also found that these characteristics are linearly interrelated. It is suggested that there is a cooperativity between various types of solute-water interactions governed by the solute structure.
authors.affiliation: Laboratory of Separation and Reaction Engineering, Department of Chemical Engineering, Faculty of Engineering of the University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal. Electronic address: ppalma@fe.up.pt.
authors.forename: Pedro P
authors.initials: PP
authors.lastname: Madeira
authors.affiliation: Laboratory of Separation and Reaction Engineering, Department of Chemical Engineering, Faculty of Engineering of the University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal.
authors.forename: Ana
authors.initials: A
authors.lastname: Bessa
authors.affiliation: LEPABE, Department of Chemical Engineering, Faculty of Engineering of the University of Porto, 4200-465 Porto, Portugal.
authors.forename: Joana A
authors.initials: JA
authors.lastname: Loureiro
authors.affiliation: Requimte, Dep. Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua Campo Alegre 687, 4169-007 Porto, Portugal.
authors.forename: Luís
authors.initials: L
authors.lastname: Álvares-Ribeiro
authors.affiliation: Laboratory of Separation and Reaction Engineering, Department of Chemical Engineering, Faculty of Engineering of the University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal.
authors.forename: Alírio E
authors.initials: AE
authors.lastname: Rodrigues
authors.affiliation: AnalizaDx Inc., 3615 Superior Avenue, Suite 4407B, Cleveland, OH 44114, USA.
authors.forename: Boris Y
authors.initials: BY
authors.lastname: Zaslavsky
mesh_terms: D000596:Amino Acids / Q000032:analysis; D001547:Benzaldehydes / Q000032:analysis; D019905:Benzyl Alcohol / Q000032:analysis; D003374:Coumarins / Q000032:analysis; D003911:Dextrans / Q000737:chemistry*; D005960:Glucosides / Q000032:analysis; D016014:Linear Models; D019800:Phenol / Q000032:analysis; D010626:Phenylethyl Alcohol / Q000032:analysis; D011092:Polyethylene Glycols / Q000737:chemistry*; D011205:Povidone / Q000737:chemistry*; D012997:Solvents / Q000737:chemistry; D014867:Water / Q000737:chemistry
chemical_list: D000596:Amino Acids; D001547:Benzaldehydes; D003374:Coumarins; D003911:Dextrans; D005960:Glucosides; D012997:Solvents; D014867:Water; D019800:Phenol; D011092:Polyethylene Glycols; C030123:coumarin; C100058:vanillin; D011205:Povidone; D019905:Benzyl Alcohol; D010626:Phenylethyl Alcohol
keywords: Aqueous two-phase partitioning; Hofmeister effect; Salt additives; Solute–water interactions; Solvatochromic comparison method