In this paper, we propose a new phenomenological two parameter parametrization of q(z) to constrain barotropic dark energy models by considering a spatially flat FRW universe, neglecting the radiation component, and reconstructing the effective equation of state (EoS). This two free-parameter EoS reconstruction shows a non-monotonic behavior, pointing to a more general fitting for the scalar field models, like thawing and freezing models. We constrain the q(z) free parameters using the observational data of the Hubble parameter obtained from cosmic chronometers, the joint-light-analysis type Ia Supernovae sample and a joint analysis from these data. We obtain a value of q(z) today, q 0 = −0.48 +0.10 −0.11 , and a transition redshift, z t = 0.71 +0.12 −0.12 (when the Universe change from an decelerated phase to an accelerated one). The effective EoS reconstruction and the ω -ω plane analysis pointed out a quintom dark energy, which is consistent with a non parametric EoS reconstruction, reported by other authors, and using the latest cosmological observations.