Solubility and transfer solvation thermodynamics of l-isoleucine and l-serine in water to aqueous solution of Na2SO4 and K2SO4 from 288.15 K to 303.15 K

Solubility analysis of homologous series of amino acids and solvation energetics in aqueous potassium sulfate solution

“…The trend of salting-out and salting-in effects are given and explain by the constant, K si , the quantitative estimate of salting-in and salting-out effects which are determined by the use of Eq. (1) [7, 19, 21] and offered in Table 4.logtrue(SSSRtrue)=KsiCwhere, S S is the solubility of amino acid in aqueous K 2 SO 4 mixtures with concentration (C) in molality, and S R is the solubility of respective amino acid in pure water.…”

“…dm- 3 )Molar Vol. (Vs) (dm 3 .mol −1 )σs (nm)Apparent Dipole Moment (μs) (D)α (x 10 3 )0.000.00001.000018.0150.9970 # 18.069210.2741.831*0.257*0.200.00360.996418.57751.0029918.522120.2751.8310.2570.300.00540.994618.85871.0059818.74660.2761.8310.2570.400.00720.992819.13991.0089718.969740.2761.8310.2570.500.00890.991119.40561.011819.179280.2761.8310.2570.650.01160.988419.82741.0162919.509590.2771.8310.257u(T) = ± 0.10 K; #, * For reference [40].Density, molar mass, size and dipole moment values of K 2 SO 4 , 2.66 g mol −1 , 174.259, and 5.92 Å respectively are taken from reference [19] and internet sources.The required diameter of glycine, DL-alanine, DL-nor-valine and DL-serine are 5.64 Å, 6.16 Å, 6.92 Å and 5.93 Å respectively [15, 16, 27]. The dipole moment of glycine, DL-alanine, DL-nor-valine and DL-serine are 15.7 D, 15.9 D, 16.0 D and 11.10 D respectively [15, 16, 27].…”

“…u(T) = ± 0.10 K; #, * For reference [40].Density, molar mass, size and dipole moment values of K 2 SO 4 , 2.66 g mol −1 , 174.259, and 5.92 Å respectively are taken from reference [19] and internet sources.The required diameter of glycine, DL-alanine, DL-nor-valine and DL-serine are 5.64 Å, 6.16 Å, 6.92 Å and 5.93 Å respectively [15, 16, 27]. The dipole moment of glycine, DL-alanine, DL-nor-valine and DL-serine are 15.7 D, 15.9 D, 16.0 D and 11.10 D respectively [15, 16, 27].…”

“…A low-to-high temperature controlling thermostat with an accuracy of ±0.10 K at atmospheric pressure (p = 0.1 MPa) was used for all measurements. The first step of the gravimetric method [15, 16, 17, 18, 19] requires the preparation of a saturated solution of amino acids in a particular electrolyte solution having a certain concentration of K 2 SO 4 at studied temperature and this solution was taken in a jacketed glass cell. The temperature was controlled at 298.15K by circulating thermo stated water in the jacket and such studied solution was continuously stirred for 12 h to achieve saturation equilibrium.…”

“…In particular, information on the thermodynamic solvation properties of amino acids in aqueous salt solutions helps to realize the conformational changes of molecules in solution produced by the addition of denaturants, or by the transport of charged solutes across membranes. So, we choose homologous series of amino acids such as glycine, D,L-alanine, D,L-nor-valine and D,L-serine and estimated saturated solubility in the presence of aqueous K 2 SO 4 solution at 298.15 K using gravimetric method [15, 16, 17, 18, 19]. We introduced our attention to find out the physicochemical and chemical factors associated with the solubility and the transfer Gibbs free energies and explained the relationship among solubility, solvation thermodynamics and stability of the studied amino acids in aqueous K 2 SO 4 solution at 298.15 K. The research will definitely be helpful to improve our knowledge in the field of amino acid research such as chemical, physical, biochemical, engineering, pharmaceutical and industrial sciences.…”