EFFECT OF TEMPERATURE AND DENSITY ON THE PERFORMANCE OF MICROPACKED COLUMNS IN SUPERCRITICAL-FLUID CHROMATOGRAPHY

The effects on the efficiency of micropacked columns in supercritical fluid chromatography (SFC) of density at fixed temperature and of temperature at fixed density were investigated. The variation of the retention and resolution achievable for a given pair of solutes with the mobile phase density under different isothermal conditions was also studied. The linear velocity was varied using several flow restrictors of different lengths and inner diameters. The column type investigated was characterized by an inside diameter of <1 mm and the use of large particles (by HPLC standards), resulting in a particle-to-column diameter ratio of 0.1-0.3. Owing to the better permeability derived from both the large particle diameters and the high value of the interparticle porosity, the use of these columns may be an interesting approach in SFC.