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 ofn-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 suitable for fast separations than SFC. The solvating ability of the mobile phase, 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 numbers as high as 80 were separated under SGC conditions using a 35 cm ×250 μm i.d. column packed with 10 μm polymer-encapsulated silica particles at 200 atm, with a temperature program of 100–380°C at 10°C min−1.