Comparison of packed capillary solvating gas chromatography with supercritical fluid chromatography using carbon dioxide as mobile phase

The efficiency (plate number per unit time) and elution power (range of it- alkanes) of packed capillary SFC and SGC using CO2 as the mobile phase were compared. A higher plate number per unit time was obtained in SGC than in SFC using the same column under the same applied conditions. SGC is more su itable for fast separations than SFC. The solvating ability of the mobile p hase, at the column exit end, decreased remarkably after the restrictor was removed. However, the elution molecular weight range in SGC can be greatly extended by increasing the column temperature. n-Alkanes with carbon numbe rs as high as 80 were separated under SGC conditions using a 35 cm x 250 mu m i.d. column packed with 10 mu m polymer-encapsulated silica particles at 200 arm, with a temperature program of 100-380 degrees C at 10 degrees C m in(-1).