PARAMETERS IN SUPERCRITICAL FLUID CHROMATOGRAPHY OF STYRENE OLIGOMERS

Supercritical fluid chromatography has been applied to the separation of the homologous species of styrene oligomers on an analytical and on a preparative scale. In all cases, a linear pressure program starting from relatively low levels of pressure has been applied for the separations. The temperature was constant and kept well above the critical temperature of the mobile-phase n-pentane/methanol. The stationary phase was porous silica. This communication reports results of an experimental investigation in which a systematic study has been carried out of the influence on resolution of the variation of the parameters for the mobile fluid phase, namely, pressure, temperature, composition, and flow rate. Several chromatograms obtained are presented and evaluated. It is shown that besides pressure and temperature, another parameter which directly concerns the fluid mobile phase is the composition of the mobile phase, if this phase is composed of two or more components.