In principle, solvation enthalpies should be easily approximated from MD force fields (i.e. using gromacs) as the difference between the total potential energy of a solvated system and the sum of those for the gas phase solute and a water box with the same number of waters as the solvated system.

My question is can this be done for ions using periodic boundaries and Ewald summation (which is usually necessary for aqueous systems using PBC.