Relative hydrophobicity of (PEG or Ucon)-salt ATPSs

• Autor(es): Silvério, Sara C. ; Madeira, Pedro ; Rodríguez, Oscar ; Teixeira, J. A. ; Macedo, Eugénia
• Data: 2008
• Identificador Persistente: http://hdl.handle.net/1822/8514
• Origem: RepositóriUM - Universidade do Minho
• Assunto(s): Aqueous two-phase systems; Partition coefficient; Hydrophobicity; Aminoacids
• Tipo de Documento: Documento de conferência
• Idioma: Inglês

Descrição

Aqueous Two-Phase Systems (ATPSs) are biphasic systems composed mainly by water. ATPSs are obtained upon mixing of two aqueous solutions of certain polymers or a polymer and a salt (above certain critical conditions, e.g. concentration, temperature). These systems are commonly indicated for the extraction of biomolecules. In this work, the partition coefficients for a series of five dinitrophenylated amino-acids (ranging from glycine to amino-caprylic acid) were determined experimentally in five different polymer-salt ATPSs (polymers: PEG or Ucon; salts: Na2SO4, Li2SO4 or (NH4)2SO4) at 23ºC. Values of the free energy of transfer of a methylene group, ΔG(CH2), for the five ATPSs were obtained from the partition coefficients and compared with ΔG(CH2) previously obtained for PEG-Na2SO4 (Rodríguez et al., 2007). Ucon-salt ATPSs presented higher values of ΔG(CH2) than the corresponding PEG-salt systems, witch indicates that the Ucon-rich phase is more hydrophobic than the PEG-rich phase.