FACTORS GOVERNING THE ANALYTICAL SUPERCRITICAL FLUID EXTRACTION AND SUPERCRITICAL FLUID CHROMATOGRAPHIC RETENTION OF POLYCYCLIC AROMATIC-HYDROCARBONS

The molecular connectivity of polycyclic aromatic hydrocarbons (PAHs) correlates well with retention data for several supercritical fluid chromatographic systems. The quantitative effect of microextractor cell geometry on supercritical fluid extraction (SFE) efficiencies of PAHs from octadecyl-bonded sorbents is compared with that seen upon varying the fluid density for the same system. Relative recoveries were increased by up to a factor of two, for coronene, by employing short broad extraction vessels, 1:1 length: I.D., compared to using long narrow vessels, 20:1 length:I.D. The average relative recovery increase was 121% with a large dependence on compound type, increasing ca. linearly with fused ring number for the PAHs studied. A similar relative recoveries increase was achievable by increasing the fluid density by 0.12 g ml-1 with a small dependence on the compound type (decreasing linearly with fused ring number).