Applications of Supercritical Fluids in Industrial Analysis

The continued search for rapid, efficient and cost-effective means of analytical measurement has introduced supercritical fluids into the field of analytical chemistry. Two areas are common: supercritical fluid chroma tography and supercritical fluid extraction. Both seek to exploit the unique properties of a gas at temperatures and pressures above the critical point. The most common supercritical fluid is carbon dioxide, employed because of its low critical temperature (31 °C), inertness, purity, non-toxicity and cheapness. Alternative supercritical fluids are also used and often in conjunction with modifiers. The combined gas-like mass transfer and liquid-like solvating characteristics have been used for improved chroma tographic separation and faster sample preparation. Supercritical fluid chromatography (SFC) is complementary to gas chro matography ( GC) and high performance liquid chromatography (HPLC), providing higher efficiency than HPLC, together with the ability to analyse thermally labile and high molecular weight analytes. Both packed and open tubular columns can be employed, providing the capability to analyse a wide range of sample types. In addition, flame ionization detection can be used, thus providing 'universal' detection.

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This volume concentrates on applications of supercritical fluids in the major industrial sectors: polymer analysis, environmental chemistry, pharmaceutical chemistry and food technology. An introduction to supercritical fluids is followed by chapters on the instrumentation available for supercritical fluid extraction and supercritical fluid chromatography.

Inhalt
1 Properties of supercritical fluids.- 1.1 Introduction.- 1.2 Fundamental studies of supercritical fluids.- 1.3 Choice of supercritical fluid for extraction.- 1.4 Prediction of solubility.- References.- 2 Instrumentation for supercritical fluid chromatography.- 2.1 The anatomy of a supercritical fluid chromatograph.- 2.2 The quality of the fluids.- 2.3 The pumps.- 2.4 Sample introduction.- 2.5 Columns.- 2.6 Restrictors.- 2.7 Detectors.- References.- 3 Instrumentation for supercritical fluid extraction.- 3.1 Introduction.- 3.2 SFE instrumentation.- 3.3 Depressurization systems.- 3.4 Collection of extracts.- 3.5 Method development.- 3.6 Conclusions.- References.- 4 Supercritical fluid chromatography and extraction of pharmaceuticals.- 4.1 Introduction.- 4.2 SFC of pharmaceuticals.- 4.3 Drugs of abuse.- 4.4 Supercritical fluid extraction.- 4.5 Conclusions.- References.- 5 Applications of supercritical fluids in polymer analysis.- 5.1 Introduction.- 5.2 Supercritical fluid chromatography.- 5.3 Applications of SFC for polymers.- 5.4 Supercritical fluid extraction.- 5.5 Applications of on-line extraction.- 5.6 Applications of off-line extraction.- 5.7 Conclusions.- References.- 6 Applications of supercritical fluids in food science.- 6.1 Chemical derivatization.- 6.2 Solid-phase extraction.- 6.3 Multidimensional chromatography.- 6.4 Drug and chemical residues.- 6.5 Vitamins.- 6.6 Lipids.- 6.7 Colours.- 6.8 Sugars.- 6.9 Waxes.- 6.10 Flavours and aromas.- Acknowledgements.- References.- 7 Supercritical fluid extraction in environmental analysis.- 7.1 Introduction.- 7.2 Practice.- 7.3 Factors affecting extraction from environmental samples.- 7.4 On-line coupling of SFE to chromatographic analysis.- 7.5 Applications.- References.- 8 Future developments in analytical supercriticalfluid technology: some ideas from recent research.- 8.1 Introduction.- 8.2 Theory and understanding.- 8.3 Instrumentation.- 8.4 Special techniques.- Acknowledgements.- References.- General index.- Index of compounds.