Activity of water, osmotic and activity coefficients of sodium glutamate and sodium aspartate in aqueous solutions at 310.15 K

Abstract

The vapor pressures of aq. solns. of sodium L-glutamate (mi = 0.05-0.57 mol kg-1) and sodium L-aspartate (mi = 0.005-0.48 mol kg-1) were precisely measured at T = 310.15 K and the activity of water and the osmotic and activity coeffs. of the solutes were calcd. from these data. The concn. dependence of the osmotic coeffs. is described with the help of the Pitzer equation and the mean spherical approxn. (MSA). It is shown that it is possible to describe thermodn. properties of sodium aspartate and sodium glutamate solns. up to 0.5 molkg-1 with distance parameter R as the single fit parameter.