Assuming that only water molecules but no electrolytes penetrate the zeosils, it is required to probe the evolution of water chemical potential in electrolyte solutions µ CnAm water (P ). In The third approach consists in using molecular simulation to calculate water chemical potential as performed by Desbiens et al. for the rigid TIP4P water model. A set of (N,P,T) simulations is performed in order to obtain the relationship between pressure and density.