Supercritical fluid methods for the analysis of complex fuel and environmental samples

The application of supercritical fluid methods can greatly improve the analysis of complex mixtures spanning wide chemical classes. In separations from complex matrices supercritical fluids can be used to improve both extraction efficiency and speed. The variable solvating powers and gas-like diffusion coefficients and viscosities can provide efficient new methods for sample enrichment, cleanup and fractionation. Supercritical fluid chromatography (SFC) is applicable to both thermally labile and less volatile materials. The use of small diameter (25- to 50-micron) fused silica capillary columns provides chromatographic efficiencies for SFC that are nearly comparable to conventional capillary gas chromatography and much greater than practical by liquid chromatography (LC). The development of practical capillary SFC-MS instrumentation, allowing both electron impact and chemical ionization mass spectrometry (MS), is expected to provide a powerful alternative to LC-MS for complex mixture analysis. Recent results will be presented on the development of methods for the analysis of fuels, labile pollutants, hazardous solid waste materials, and related complex environmental mixtures. The application of various supercritical fluids for sample extraction, SFC and SFC-MS, and the recent development of a system for automated supercritical fluid extraction-chromatography will also be described. Finally, the potential role of supercritical fluid methods in routine chemical analysis will be discussed.