Influence of biocompatible ammonium ionic liquids on the solubility of l-alanine and l-valine in water

T. Vasantha, Awanish Kumar, Pankaj Attri, Pannuru Venkatesu, R. S. Rama Devi

Research output: Contribution to journalArticlepeer-review

28 Citations (Scopus)


Understanding the folding process of proteins or polypeptides in co-solvents is a fascinating and critical issue in biophysical chemistry. In recent years, ionic liquids (ILs) represent a versatility of the new class of co-solvents. To quantify the bimolecular interactions of amino acids (AA), such as l-alanine (Ala) and l-valine (Val) with biocompatible ILs, we report the apparent transfer free energies (ΔG'tr) for AA from water to aqueous solutions of six ammonium based ILs (diethylammonium acetate (DEAA), diethylammonium sulfate (DEAS), triethyl ammonium acetate (TEAA), triethylammonium sulfate (TEAS), triethylammonium dihydrogen phosphate (TEAP), and trimethylammonium acetate (TMAA)) through solubility measurements, as a function of IL concentration at 298.15. K under atmospheric pressure. Salting-out effect was found for AA in aqueous IL solutions with increasing IL concentrations. In addition, we observed positive values of ΔG'tr for Ala and Val from water to ILs, indicating that the interactions between ILs and AA are unfavorable. From the solubility results, we envisage that the selected ammonium based-ILs provide stability to the structure of AA. Further, the stability of AA has been studied by means of the UV-vis spectroscopy.

Original languageEnglish
Pages (from-to)39-45
Number of pages7
JournalFluid Phase Equilibria
Publication statusPublished - Dec 15 2012
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Chemical Engineering(all)
  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry


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