SEARCH Articles Figures Tables Acid-base extractions, sample fractionation Base fraction analysis Base-mole-fraction Characterization of Crude Oils and Petroleum Fractions Based on Structural Analysis Characterization of Petroleum Fractions Based on Chemical Reactions Definitions based on mole fractions Fractionation of Ethylene-Based Copolymers Fractions from acid-base separations Standard state based on mole fractions Weak base fractional composition