Utilize este identificador para referenciar este registo:
https://hdl.handle.net/1822/16856
Título: | Salt effect on the (polyethylene glycol 8000 + sodium sulfate) aqueoustwo-phase system : relative hydrophobicity of the equilibrium phases |
Autor(es): | Ferreira, Luísa A. Teixeira, J. A. |
Palavras-chave: | Aqueous two-phase systems Salt effect Relative hydrophobicity Gibbs free energy of transfer |
Data: | Jul-2011 |
Editora: | Elsevier 1 |
Revista: | Journal of Chemical Thermodynamics |
Resumo(s): | The relative hydrophobicity of the phases of several {polyethylene glycol (PEG) 8000 + sodium sulfate (Na2SO4)} aqueous two-phase systems (ATPSs), all containing 0.01 mol.L-1 sodium phosphate buffer (NaPB, pH 7.4) and increasing concentration of a salt additive, NaCl or KCl, up to 1.0 mol.L-1, was measured by the free energy of transfer of a methylene group between the phases, DG(CH2). The DG(CH2) of the systems was determined by partitioning of a homologous series of five sodium salts of dinitrophenylated (DNP) – amino acids with aliphatic side chains in three different tie-lines of each biphasic system. The relative hydrophobicity of the phases ranged from -0.125 to -0.183 kcal.mol.L-1, being the NaCl salt the one to provide the more effective changes. The results show that, within each system, there is a linear relationship between the DG(CH2) and the tie-line length (TLL), and biphasic systems with high salt additive concentration present the most negative DG(CH2) values. Therefore, the feasibility of establishing a relationship between the relative hydrophobicity of the phases in a given TLL and the ionic strength of the salt additive was investigated and a satisfactory correlation was found for each salt. |
Tipo: | Artigo |
URI: | https://hdl.handle.net/1822/16856 |
DOI: | 10.1016/j.jct.2011.03.014 |
ISSN: | 0021-9614 |
Outros identificadores: | 0021-9614 1096-3626 |
Arbitragem científica: | yes |
Acesso: | Acesso aberto |
Aparece nas coleções: | CEB - Publicações em Revistas/Séries Internacionais / Publications in International Journals/Series |