STUDIES OF LINEAR RESTRICTORS AND ANALYTE COLLECTION VIA SOLVENT TRAPPING AFTER SUPERCRITICAL FLUID EXTRACTION

The plugging of restrictors and the trapping of analytes after off-line supercritical fluid extraction (SFE) have been problematic for many workers. The temperature and volume of the trapping solvent both have an effect on the trapping of analytes, but dynamic mixing, the presence of inert bodies in the trapping solvent, and the shape of a secondary trapping device (dry collection surface) do not seem to have a major effect. Heating (50°-250°C) the entire length of the restrictor eliminates the restrictor plugging problem for the analytes studied. The heating of the restrictors does not cause the decomposition of thermally labile compounds. The coupling of the heated restrictor with dual-chamber trapping vial gives excellent performance. Quantitative recovery of polychlorinated biphenyls (PCBs) from sewage sludge and polynuclear aromatic hydrocarbons (PAHs) from marine sediment and mussel tissue is achieved using this optimized restrictor and trapping design after off-line SFE. © 1992 Oxford University Press.