Evaluation of oligomeric models of coal asphaltenes and preasphaltenes as GPC calibration standards. [Gel permeation chromatography]

Polystyrene, oligo(phenyl ethers) and/or oligo(phenyl methylenes) are suitable gel permeation chromatography (GPC) calibration standards for most derivatized solvent refined lignite (SRL) asphaltenes and preasphaltenes. More condensed aromatic oligomers (i.e., containing phenanthryl and pyrenyl moieties) may be required for accurate GPC determination of the molecular weights of SRL samples with low H/sub aru//C/ar/ (highly condensed aromatics). The SRL samples must be derivatized to block free -OH groups and prevent interaction with the GPC solvent, tetrahydrofuran. 15 references, 2 figures.