A method for separating mixtures of chemical compounds based on the difference in their chemical and physical properties. There are two types of chromatography (1) Gas Chromatography (GC): The petroleum hydrocarbons are separated in a gas phase mixed with Helium and Nitrogen through a liquid stationary phase to desorb the separated hydrcarbons according to their molecular size and type. The second type of chromatography (2) Liquid chromatography (LC) : The petroleum hydrocarbons (saturates) pass in n-C6 or n-C7 through an adsorbent column such as alumina or silica gel. These separated components can be collected, analyzed, or both, at the end of the chromatographic path.