Analysis with Supercritical Fluids: Extraction and Chromatography

1 SFC and SFE: An Introduction for Novices.- 2 Physico-Chemical Principles of Supercritical Fluid Separation Processes.- 2.1 Introduction.- 2.2 Physico-Chemical Properties of Pure Supercritical Solvents.- 2.2.1 Thermodynamic Properties.- 2.2.2 Dielectric Properties.- 2.2.3 Transport Properties.- 2.3 Phase Equilibria of Fluid Mixtures.- 2.3.1 Phase-Theoretical Aspects.- 2.3.2 Classification of Binary Critical Phase Behavior By “Families”.- 2.3.3 Ternary Systems.- 2.3.4 Quaternary Systems.- 2.3.5 Solubility of Solids in Supercritical Solvents.- 2.3.6 Isothermal Pressure (Concentration) Phase Diagrams.- 2.3.7 Calculation and Correlation of Fluid Phase Equilibria.- 2.4 Physico-Chemical Applications of Sfc.- 2.4.1 Capacity Ratios.- 2.4.2 Diffusion Coefficients.- References.- 3 Basic Principles of Analytical Supercritical Fluid Extraction.- 3.1 The Development of Analytical SFE.- 3.1.1 Sample Preparation in Analytical Chemistry.- 3.1.2 Utilization of Supercritical Fluids in Analytical-Scale Extractions.- 3.1.3 Features of Analytical SFE.- 3.2 Fluid Properties in SFE.- 3.2.1 Selection of The Supercritical Fluid.- 3.2.2 Unique Properties of Supercritical Fluid Carbon Dioxide.- 3.2.3 The Use of Cosolvents in SFE.- 3.3 Optimizing Experimental Conditions For Analytical SFE.- 3.3.1 Objectives of The Extraction.- 3.3.2 Critical Parameters Pertinent To SFE.- 3.3.3 A Theoretical Approach For Optimizing SFE.- 3.4 The Relevance of Sfc-Derived Data To Analytical SFE.- 3.4.1 Relevant Measurements By SFC.- 3.4.2 Implications For SFE.- 3.5 The Practice of Analytical SFE.- 3.5.1 Equipment Requirements.- 3.5.2 Experimental Considerations in Analytical SFE.- 3.6 Sample Matrix Effects in SFE.- 3.6.1 Physical Matrix Effects.- 3.6.2 Chemical Changes in The Sample Matrix.- 3.6.3 Impact of Matrix On Extraction Kinetics.- 3.7 Problems and Future Research Needs in Analytical SFE.- References.- 4 Coupled Supercritical Fluid Extraction-Capillary Gas Chromatography (SFE-GC).- 4.1 introduction.- 4.2 Performing SFE-GC.- 4.2.1 instrumentation and Methods.- 4.2.2 Fluids and Extraction Conditions Used For SFE-GC.- 4.3 Abilities and Limitations of Split and On-Column SFE-GC.- 4.3.1 Chromatographic Peak Shapes Obtained Using SFE-GC.- 4.3.2 Quantitation Using SFE-GC.- 4.3.3 Speed of SFE-GC Analyses.- 4.3.4 Sensitivity and Sample Sizes.- 4.3.5 Sample Types and Matrix Considerations.- 4.4 Summary.- References.- 5 Gradients in SFC.- 5.1 Overview.- 5.2 Temperature Gradients.- 5.3 Pressure Gradients.- 5.4 Density Gradients.- 5.5 Velocity Gradients.- 5.6 References.- 6 injection Techniques in SFC.- 6.1 introduction.- 6.2 The Physical State of The Sample.- 6.3 introduction of Supercritical Fluid Extracts.- 6.4 introducing a Solution.- 6.5 Peak Focusing.- 6.6 Direct injection.- 6.7 Open Split (Dynamic Split) injection.- 6.8 Timed Split injection.- 6.9 Solvent Effects on Peak Shape.- 6.10 Solvent Venting with A Precolumn.- 6.11 Solvent Backflush.- 6.12 Solvent Venting with Gas Purging.- 6.13 Sample Losses in The injector.- References.- 7 Stationary Phases For Packed Column Supercritical Fluid Chromatography.- 7.1 introduction.- 7.2 Physical Properties of Column Packings.- 7.3 influence of Substrate Morphology on The Properties of Chemically Bonded Phases in SFC.- 7.4 influence of Surface Heterogeneity on The Properties of Chemically Bonded Phases.- 7.4.1 Chemical interactions with Silanol Groups.- 7.4.2 Deactivation of Silanol Groups with Mobile Phase Modifiers.- 7.4.3 Shielding of Silanol Groups By Polymer Encapsulation.- 7.5 Macroporous Polymeric Packings.- 7.6 Column Packings Used For Special Applications.- 7.7 Conclusions.- References.- 8 Enantiomer Separation By Capillary Supercritical Fluid Chromatography.- 8.1 introduction.- 8.2 General Aspects.- 8.2.1 Temperature.- 8.2.2 Speed of Analysis and Efficiency.- 8.2.3 Mobile Phase.- 8.2.4 Column Loadability.- 8.3 Packed Column SFC.- 8.4 Open Tubular Column SFC.- 8.5 Conclusion.- References.- 9 Supercritical Fluid Chromatography/Mass Spectrometry.- 9.1 introduction.- 9.2 Early investigations of SFC/MS.- 9.3 SFC/MS Using Direct introduction interfaces.- 9.3.1 Flow Restriction.- 9.3.2 Ionization Methods.- 9.3.2.1 Chemical Ionization.- 9.3.2.2 Electron Ionization and Charge Exchange.- 9.3.2.3 Secondary Ion Mass Spectrometry.- 9.3.3 Type of Mass Analyzer.- 9.3.3.1 DFI SFC/MS Using Quadrupole Mass Spectrometers.- 9.3.3.2 DFI SFC/MS Using Double-Focussing Sector Mass Spectrometers.- 9.3.3.3 DFI SFC/MS Using Fourier Transform Mass Spectrometers.- 9.4 SFC/MS Using High-Flow-Rate interfaces.- 9.4.1 SFC/MS Using The Moving Belt interface.- 9.4.2 SFC/MS Using The Particle Beam interface.- 9.4.3 off-Line SFC/MS.- 9.4.4 SFC/MS Using Direct introduction of Split Effluents.- 9.4.5 SFC/MS Using Post-Expansion Splitting.- 9.4.6 SFC/MS Using The Thermospray interface.- 9.5 Supercritical Fluid injection/Mass Spectrometry.- 9.6 Conclusion.- References.- 10 Supercritical Fluid Chromatography with FT-IR Detection.- 10.1 introduction.- 10.2 Flow Cell Approach.- 10.3 Solvent Elimination Approach.- 10.4 Summary.- References.- 11 Supersonic Jet Spectroscopy with Supercritical Fluids.- 11.1 introduction.- 11.2 Supersonic Jet Spectroscopy.- 11.2.1 Principles of Supersonic Expansions.- 11.2.2 Spectroscopic Methods For Detection.- 11.3 High Pressure Fluid injection For Nonvolatile Samples.- 11.3.1 Experimental.- 11.3.2 Supercritical Fluid injection.- 11.3.3 High Pressure Liquid injection.- 11.4 Supercritical Fluid Chromatography and Supersonic Jet Spectroscopy.- 11.4.1 Experimental.- 11.4.2 The interfaces.- 11.5 Conclusions.- References.- Basic References Analytical Scale SFC/SFE.- Recommended Literature.