Analysis of non-saponifiable lipids by super-/subcritical- fluid chromatography

Because of the particular properties of carbon dioxide or carbon dioxide/mo difier mobile phases, super- or subcritical-fluid chromatography (SFC) can be an alternative to more classical chromatographic methods such as gas chr omatography (GC) or high-performance liquid chromatography (HPLC) for the s eparation of unsaponifiable lipids. These fluids can also be helpful in the extraction and/or the concentration steps of sterols, tocopherols or carot enoids from complex samples. Supercritical extraction, off-line prefraction ation or semi-preparative supercritical fluid chromatography, carried out b efore the analysis are described. The effects on separation of analytical p arameters such as pressure, nature of and modifier percentage or stationary phase nature are also reported. The performance of capillary, packed or ca pillary packed columns is discussed, as well as the consequences of their u se (choice of stationary phases, type of coupled detector). Numerous exampl es of fine separations are reported. (C) 2001 Elsevier Science B.V. All rig hts reserved.