Water activity in aqueous amino acid solutions, with and without KCl, at 298.15 K

• Author(s): Pinho, Simão
• Date: 2007
• Persistent ID: http://hdl.handle.net/10198/2833
• Origin: Biblioteca Digital do IPB
• Subject(s): Water activity; Electrolyte; Amino acids; Measurement
• Document Type: Conference object
• Language: English
• Contributor(s): Biblioteca Digital do IPB

Description

The study of physical chemical properties of amino acids (AA) aqueous solutions have been a very important studied subject, not only because they are the basic building blocks of proteins and peptides but also for their importance in industrial processes, particularly for pharmaceutical and food industries. In this work an humidity sensor instrument was used to measure water activity in aqueous solutions of DLalanine, glycine or L-serine with potassium chloride, molality ranging form 0.0 to 3.0. The reliability of the method was checked comparing the experimental data with literature values, proving to be very accurate. The calculated AA molal activity coefficients showed good consistency with those obtained using the isopiestic method, and the ternary data is very useful to extend the capabilities of thermodynamic models to higher salt and AA concentrations.