Partial molar volumes of glycine and L-Alanine in aqueous MgSO4 solutions between 278.15 and 308.15 K

In this work, partial molar volumes of glycine and L-alanine in aqueous solutions of magnesium sulphate at (0.0, 0.1, 0.3, 0.7 and 1.0) molal were obtained between 278.15 K and 308.15 K. Additionally, partial molar volumes of transfer at infinite dilution and hydration numbers were calculated. In general, transfer volumes are higher for glycine then L-alanine. From the transfer volumes, it can be concluded that the predominant interactions are pairwise between ions and zwitterionic centers of the amino acids. On the other hand, hydration numbers are higher for L-alanine than glycine. Dehydration of the studied amino acids is observed, rising either temperature or salt molality.
This work is supported by project Project PEst-C/EQB/LA0020/2013, financed by FEDER through COMPETE - Programa Operacional Factores de Competitividade and by FCT - Fundação para a Ciência e a Tecnologia. This work was also co-financed by QREN, ON2 and FEDER (Project NORTE-07-0162-FEDER-000050).

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