  We discuss the isospin effect on the possible phase transition from hadronic
to quark matter at high baryon density and finite temperatures. The
two-Equation of State (Two-EoS) model is adopted to describe the hadron-quark
phase transition in dense matter formed in heavy-ion collisions. For the hadron
sector we use Relativistic Mean Field (RMF) effective models, already tested on
heavy ion collision (HIC). For the quark phase we consider various effective
models, the MIT-Bag static picture, the Nambu--Jona-Lasinio (NJL) approach with
chiral dynamics and finally the NJL coupled to the Polyakov-loop field (PNJL),
which includes both chiral and (de)confinement dynamics. The idea is to extract
mixed phase properties which appear robust with respect to the model
differences. In particular we focus on the phase transitions of isospin
asymmetric matter, with two main results: i) an earlier transition to a mixed
hadron-quark phase, at lower baryon density/chemical potential with respect to
symmetric matter; ii) an "Isospin Distillation" to the quark component of the
mixed phase, with predicted effects on the final hadron production. Possible
observation signals are suggested to probe in heavy-ion collision experiments
at intermediate energies, in the range of the NICA program.
