Klesper, Corwin and Turner first demonstrated Supercritical Fluid Chromatography (SFC) in "Communications to the editor entitled High Pressure Gas Chromatography above Critical Temperatures" in 1962. They used dichlorodifluoromethane (Tc = 112°C) and monochlorodifuloromethane (Tc = 96 °C) and at the pressures above 1000 psi and 1400 psi, respectively, to elute Ni etioporphyrin II and etioporphyrin II from polyethylene glycol stationary phase. They even stated "The porphyrins could be recovered at the outlet valve." This means that they already predicted the possibility of preparative SFC. Figure 1 shows the historical SFC apparatus described in ref. (1). Sie, Beersum and Rijnders published a series of articles on "High-Pressure Gas Chromatography with Supercritical Fluids" in Separation Science in 1966 and 1967. In these articles, they extensively used carbon dioxide as mobile phase and thoroughly studied its behavior from both theoretical and experimental points of view.