A new apparatus for the study of high-pressure phase equilibria at low temperatures using an analytical method was designed, assembled and tested. The apparatus was specially developed for the study of multi-phase equilibria in systems containing hydrocarbons, water and hydrate inhibitors, at temperatures ranging from 213K to 353 K and pressures up to 40 MPa. The core of the apparatus is a variable-volume equilibrium cell, equipped with a 360 sapphire window and connected to an analytical system by three capillary samplers. The quality of the apparatus was confirmed through several tests, including the study of the system methane + water. An equilibrium point for the quaternary system methane + n-hexane + methanol + water is also presented. (C) 2012 Elsevier B.V. All rights reserved.