Effect of temperature on volumetric and isentropic compressibility of glycine in aqueous KCl/NaCl solutions

Riyazuddeen, Imran Khan

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Density (ρ) and ultrasonic velocity (u) values of glycine in 1.0 M aqueous KCl and 1.0 M aqueous NaCl solutions have been measured as a function of amino acids concentration at T = (298.15, 303.15, 308.15, 313.15, 318.15 and 323.15) K. Using the ρ and u data, the thermodynamic parameters such as partial molal volume (φ{symbol}0 v), isentropic compressibility (κs), change in isentropic compressibility (Δκs), relative change (Δκs0) in isentropic compressibility and partial molal isentropic compressibility (φ{symbol}0 k), values have been computed. The increase in partial molal volume with temperature is attributed to the volume expansion of hydrated zwitterions. The φ{symbol}0 v and φ{symbol}0 k values of glycine in 1.0 M aqueous KCl and NaCl solutions are larger than the corresponding values in water. The larger partial molal volumes of glycine in 1.0 M aqueous KCl and NaCl is ascribed to the formation of 'zwitterion-K+/Na+/Cl-' and 'K+/Na+/Cl--water dipole' aggregates in solutions. The variation of κs, Δκs and Δκs0 with amino acid/zwitterions concentration and temperature is discussed in terms of zwitterions-ions, zwitterions-water dipoles, ion-ion, ion-water dipoles due to intermolecular/interionic interactions occurring in the systems.

Original languageEnglish
Pages (from-to)57-62
Number of pages6
JournalJournal of Molecular Liquids
Issue number1-3
Publication statusPublished - Mar 15 2010



  • Isentropic compressibility
  • Partial molal isentropic compressibility
  • Partial molal volume
  • Zwitterion-ion interactions

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Condensed Matter Physics
  • Spectroscopy
  • Physical and Theoretical Chemistry
  • Materials Chemistry

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