Effects of pressure and temperature on the solubility of monosodium L-glutamate monohydrate in water

The solubility of monosodium L-glutamate monohydrate (MSG.H2O) in water was measured at pressures in the range of 0.10-300 MPa and 298.15 K. The density of MSG solution at high concentrations and heat of solution at saturated concentration were also measured at atmospheric pressure. The solubility, m,, increased with increasing pressure and the pressure coefficient, theta(p) [equivalent to(partial derivative ln m(s)/partial derivativep)(T)], at 0. 10 MPa was (2.0 +/- 0.1) x 10(-10) Pa-1. It agrees well with (2.1 +/- 0.2) x 10(-10) Pa-1 thermodynamically estimated using the partial molar volume, the activity coefficient of the solute in solution, and the molar volume of the crystal. The excellent agreement at 0.10 MPa gives us confidence in the solubility data at higher pressures. The heat of solution data and other pertinent values were used to calculate the temperature coefficient of solubility, theta(T) [equivalent to(partial derivative ln ms/partial derivative(1/T))(p)], by a thermodynamic equality. The resulting theta(T) compares well with the data directly measured by Ogawa.