RT Journal Article T1 Water/polyethylene glycol/sodium citrate: from the aqueous two-phase system to the complete phase diagram A1 Gómez Pineda, René A1 Soto Campos, Ana María A1 Rodríguez Figueiras, Óscar A1 Olaya López, María del Mar A1 Marcilla Gomis, Antonio K1 ATPS K1 Phase diagram K1 Temperature K1 Molecular weight K1 Solubility AB Polyethylene glycol (PEG) 6000, 10,000, or 20,000/sodium citrate Aqueous Two-Phase Systems (ATPS) were characterized at 283.2, 298.2, and 313.2 K. The compositions of the equilibrium phases were determined using an analysis procedure based on density and refractive index measurements. The complete liquid-liquid equilibrium region was obtained up to the point of solid phase precipitation, and the binodal curve was constructed from the endpoints of the experimental tie-lines. The effects of both temperature and polymer molecular weight were analyzed. Furthermore, the entire phase diagram was established using the analysis procedure based on physical property measurements, enabling experimental determination of all singular points that define the solid-liquid, solid-liquid-liquid, and solid-solid-liquid regions. Data correlation for all equilibrium compositions was carried out individually at 283.2 K, where the solid salt was present as a pentahydrate, and simultaneously at 298.2 and 313.2 K, where the salt was dihydrated, using the classical NRTL equation. The model successfully correlated all phase diagrams with standard deviations between experimental and correlated data below 1.6 wt% in all cases PB Elsevier YR 2025 FD 2025-11-01 LK https://hdl.handle.net/10347/44080 UL https://hdl.handle.net/10347/44080 LA eng NO Gómez-Pineda, R., Soto, A., Rodríguez, O., Olaya, M. del M., & Marcilla, A. (2026). Water/polyethylene glycol/sodium citrate: From the aqueous two-phase system to the complete phase diagram. Fluid Phase Equilibria, 602, 114612. https://doi.org/10.1016/j.fluid.2025.114612 NO “ERDF A way of making Europe” by the European Union. Grant ED431B 2023/022 funded by Xunta de Galicia -Spain DS Minerva RD 3 may 2026