Supercritical Fluid Chromatography is a chromatographic technique in which the mobile phase, typically carbon dioxide, is taken to pressures and temperatures above its critical point. The supercritical fluid possesses densities and other properties that are intermediate between those of gases and liquids. Unique separation capabilities become possible for compounds that are not easily volatilized for gas chromatography (GC) and solubility properties occur for replacement of normal phase, high pressure liquid chromatography (HPLC) separations. Due to the “green” solvent properties, SFC is becoming the preferred separation method over HPLC. ASTM committee D02 has approved methods using supercritical fluid chromatography for group-type separations for testing gasoline, diesel and aviation products. These methods take advantage of the unique solubility to achieve a group type separation and the use of the most common universal detector in GC, the flame ionization detector.