Gel permeation chromatography of asphalts and asphaltenes. Part I. Fractionation procedure

Abstract The experimental details of fractionation by gel permeation chromatography (GPC) of asphalts and asphalt constituents are given. Gel preparation, column design, and packing procedure as well as sample preparation are described at some length. Fractionation of a low molecular weight polybutene sample shows that under the given experimental conditions GPC separates as efficiently as gradient chromatography (BAKER‐WILLIAMS). The elution curves of three paving asphalts, their asphaltenes, and maltenes, and of two industrial air‐blown asphalts are compared and discussed. The characteristic shapes of the elution curves, together with molecular weight determinations on some fractions demonstrate three items: Extensive fractionation was achieved. The molecular weight distributions of different asphalts vary considerably. Fractionation of asphalts by solvent precipitation is much less effective than GPC as demonstrated by the large overlap of molecular weights of the asphaltene and the maltene portions of an asphalt.