Abstract |
The physical properties of supercritical fluids allow similar solvent strengths as liquids, but with higher diffusion coefficients, lower viscosities and an extended temperature range which provides the potential for more rapid and efficient extraction rates than possible with liquids. The report describes expanded studies conducted to evaluate the applicability and efficiency of analytical supercritical fluid extraction and related methodologies. These studies included the development of quantitative off-line supercritical fluid extraction methodology and a comparison to traditional Soxhlet extraction, the development and evaluation of on-line supercritical fluid extraction-gas chromatography for combined sample preparation and analysis, and direct supercritical fluid extraction-mass spectrometry for the monitoring of specific extraction profiles as a function of time. The sample matrices included an air particulate sample and XAD-2 resin, polyurethane foam, and Spherocarb adsorbents that were spiked with various model compounds. Carbon dioxide, isobutane, and methanol modified (20 mole %) carbon dioxide were utilized as supercritical fluid systems. Related studies on the evaluation of the quantitative analysis capability of a fluorescence detection supercritical fluid chromatography method and the development of viable solute focusing methods for capillary supercritical fluid chromatography were also conducted. |