The maltene (deasphaltened) fraction of an oil or a bitumen (soxhlet extract of source rock) can be fractionated in three fractions: saturated hydrocarbons, aromatic hydrocarbons and resins (NSO), using column chromatography in an alumina silica column with elution solvents of increasing polarity. The sample is diluted in n-pentane and loaded onto the column. Saturated hydrocarbons fraction is eluted with n-pentane, aromatic hydrocarbon fraction with toluene and resins (NSO) fraction with a mixture of toluene and methanol (60/40 vol.). The elution solvents are evaporated to dryness in nitrogen stream and the sample’s fractions are determined gravimetrically.