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Capillary supercritical fluid chromatography (SFC) can be used to migrate and elute high-molecular-weight compounds that are present in coal-derived products, but the complexities of these mixtures surpass the resolving capabilities of this high resolution technique. In this study, the problem of sample complexity was addressed in two ways: (a) supercritical fluid sample prefractionation, and (b) capillary SFC with selective detection. For prefractionation, a supercritical fluid extraction/fractionation system was constructed and evaluated. A number of complex coal- and petroleum-derived materials were fractionated according to the number of aromatic rings using columns packed with an NH sub 2 -modified stationary phase bonded on silica particles, and the group type separation of aliphatics, olefins, and aromatics was accomplished with a combination of silica and silver nitrate-modified columns. (ERA citation 12:019903)