  In this letter we show that the presence of the long-range Coulomb force in
dense stellar matter implies that the total charge cannot be associated with a
chemical potential, even if it is a conserved quantity. As a further
consequence, the analytical properties of the partition sum are modified,
changing the order of the phase transitions and affecting the possible
occurrence of critical behaviours. The peculiar thermodynamic properties of the
system can be understood introducing a model hamiltonian in which each charge
is independently neutralized by a uniform background of opposite charge.
