Hydrodynahic Volume Fluctuation of Polystyrene by Column Temperature and Its Effect To Retention Volume in Size Exclusion Chromatography

Abstract

The fluctuation in hydrodynamic volume of polystyrene in several solvents was evaluated by changing solvent temperature and the relation between the magnitude of the fluctuations and the retention volume change was experimentally examined. Limiting viscosity numbers of polystyrene in tetrahydrofuran(THF), chloroform, toluene, cyclohexane, and a benzene-methanol mixed solvent (77.8/22.2 vol/vol) were measured by using a Ubbelohde-type viscometer. Temperature dependence of limiting viscosity number of the polystyrene solution was observed in some range of temperature, where a change of the retention volume of polystyrene would be assumed to be observed with the change of column temperature because of the change of its hydrodynamic volume in solution. The examination of the temperature dependence of retention volume in SEC for polystyrene standards confirmed this effect. The recommended column temperature is in the range where the temperature dependence of the limiting viscosity number of polystyrene solutions is negligible; e.g., at 25°–50° C for THF, 35°–65°C for toluene, and 20°–30° C and 45°–55° C for chloroform. Column temperature in the range of 30°–45° C in chloroform is also recommended because of counterbalance of several effects to retention volume fluctuation.