| Abstract: | The Mettler/Paar precision density meter DMA-02D has been used to determine the concentration of saturated solutions of amino acids at 20.0, 25.0, and 29.8 °C. The technique has proven itself an elegant and precise method. The solubilities of all of the amino acids with the exceptions of proline, lysine, and cystine have been measured. The Gibbs free energies of transfer from saturated water solution to 1M Na2SO4 and to 1M Gu·HCL along with the van't Hoff heats and entropies have been calculated. The van't Hoff heats have been compared with the calorimetrically determined heats for some of the amino acids. The Lumry-Rajender relation between the entropy and heats has been observed. The process of transfer of the amino acids from water to the solvents is primarily enthalpic rather than entropic. |
