A thermodynamic study of retention of poly(ethylene glycol)s in liquid adsorption chromatography on reversed phases

The retention behaviour of poly(ethylene glycol)s (PEGs) on various reversed phase columns has been studied in liquid interaction chromatography at different temperatures. Similar separations could be achieved in different mobile phases. In methanol-water practically no temperature dependence was observed, while in acetone-water retention decreased with increasing temperature. From the van't Hoff plots the thermodynamic parameters were calculated, which showed, that retention is driven by enthalpy in methanol-water, while in acetone-water the driving force is entropy.