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Advisor(s)
Abstract(s)
In the recent past a considerable body of work has been published on the
measurement of activity coefficients and solubility data in aqueous amino
acid solutions containing electrolytes [1]. However, no information on water
activity in this type of system has yet been published [2].
In this work water activity (aw) in DL-alanine, glycine or L-serine aqueous
systems with ammonium sulfate, at 298.15 K, was measured. The
LabMASTER-aw water activity instrument (Novasina, Switzerland) was
used to perform the measurements. The instrument, with a controlled
chamber temperature (± 0.2 K), shows high precision (± 0.001 aw units).
The new experimental data was used to test different theoretical schemes
such as Zdanovskii-Stokes-Robinson (ZSR) model [3] and its extension, or
the Clegg-Seinfeld-Brimblecombe (CSB) approach [4], in the calculation of
amino acid and electrolyte activity coefficients in those solutions.
Comparisons between the different approaches are given.
Description
Keywords
Water activity Electrolyte Amino acids Measurement
Pedagogical Context
Citation
Fernandes, Isa; Vilarinho, Mário; Pinho, Simão (2008). Experimental and theoretical studies on water activity: aqueous solutions of amino acids with electrolytes. In 23rd European Symposium on Applied Thermodynamics. Cannes