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Author(s): Sara Silvério
Jesus Gracia
José A. Teixeira
Maria Eugénia Macedo
Title: Polyethylene glycol 8000+citrate salts aqueous two-phase systems: Relative hydrophobicity of the equilibrium phases
Issue Date: 2016
Abstract: The Gibbs free energy of transfer of a methylene group, Delta G*(CH2), is reported as a measure of the relative hydrophobicity of the equilibrium phases. Furthermore, Delta G*(CH2) is a characteristic parameter of each tie-line, and for that reason can be used for comparing different tie-lines of a given aqueous two-phase system (ATPS) or even to establish comparisons among different ATPSs. In this work, the partition coefficients of a series of four dinitrophenylated-amino acids were experimentally determined, at 23 degrees C, in five different tie-lines of PEG8000-(sodium or potassium) citrate ATPSs. Delta G*(CH2) values were calculated from the partition coefficients and used to evaluate the relative hydrophobicity of the equilibrium phases. PEG8000-potassium citrate ATPSs presented larger relative hydrophobicity than PEG8000-sodium citrate ATPSs. Furthermore, the results obtained indicated that the PEG-rich phase (top phase) has higher affinity to participate in hydrophobic hydration interactions than the salt-rich phase (bottom phase). 2015 Elsevier B.V. All rights reserved.
Subject: Ciências Tecnológicas, Ciências da engenharia e tecnologias
Technological sciences, Engineering and technology
Related Information: info:eu-repo/grantAgreement/FCT - Fundação para a Ciência e Tecnologia/Projetos Estratégicos/UID/EQU/50020/2013- POCI-01-0145-FEDER-006984/Laboratório de Processos de Separação e Reação - Laboratório de Catálise e Materiais/LSRE-LCM
Document Type: Artigo em Revista Científica Internacional
Rights: restrictedAccess
Appears in Collections:FEUP - Artigo em Revista Científica Internacional

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