Characterization of Crude Oils by Gel Permeation Chromatography

Unit sheet weights of asphalt fractions determined by structural analysis

“…The GPC molecular size distributions for the two fractionated asphalts are shown with their equivalent molecular weights in Figure 2. These distributions may also be deter- GPC separations may be affected by the types of molecular material present (24)(25)(26)(27). A bulky paraffinic group may have the same size and thus the same elution volume as a compact aromatic group of a higher molecular weight.…”

Multimode separation of polycyclic aromatic compounds by size exclusion chromatography with poly(divinylbenzene)

“…Compounds were further classified into cataannelated or pericondensed PAC, two basic types descriptive of polycyclic ring structure. These two classes of PAC can demonstrate markedly different retention behavior as evidenced by the demonstration of the pericondensation effect mentioned earlier (20,21).…”

“…The elution volumes for the parent PAC (20,25, and 35 in Figure 6) are shown to be equal to Vca, except in the case of pyrene [38], which is pericondensed and elutes later than the cataannelated species. The substituent effects can be summarized as follows: (1) The addition of alkyl or phenyl groups shifted retention to lower volumes.…”

“…For example, multimode SEC has been useful for the characterization of petroleum (8,10); for the determination of alcohols in gasoline (17), and for obtaining difficult separations (18,19). Also, a pronounced nonsize effect often observed with pericondensed PAC has proved useful for the characterization of petroleum crudes (20,21). Furthermore, with the Sephadex gels, chromatographic conditions have often been altered to exaggerate a specific nonsize effect such as adsorption or hydrogen bonding to obtain a desired separation (22)(23)(24).…”

Determination of molecular weight distributions of polymerized petroleum pitch by gel permeation chromatography with quinoline eluent

“…Quantitative characterization of pitches and polymeric pitches for molecular weight distribution by gel permeation chromatography has generally been plagued by nonideal elution behavior of the smaller molecular weight constituents (4)(5)(6)(7)(8)(9)(10) and by insufficient solubility of the higher molecular weight constituents (11). The nonideal elution behavior, particularly noticeable for the pericondensed polynuclear aromatics, has been observed in tetrahydrofuran (8), toluene 0003-2700/80/0352-1877801.00/0 (9), benzene (9, 10), and methylene chloride (4, 5).…”