ABSTRACT
PREPARATION 110
II. SUPERCRITICAL FLUID EXTRACTION (SFE) 112
A. Basic Principles of SFE 112
B. Types of Extraction and Instrumentation 117
C. The Sample Matrix and Its Preparation for SFE 122
D. The Problem with Coextractives and Water 125
E. Collection of the Extracted Analyte 128
III. INTEGRATION OF CLEANUP STEP WITH SFE 131
A. Fluid Density-Based Fractionation 132
B. Use of Adsorbents with SFE 135
C. Inverse SFE 139
D. Variation in Extraction Fluid Type
or Composition 140
IV. COUPLING REACTION CHEMISTRY
(DERIVATIZATION) WITH SFE 142
A. Reactions in Supercritical Fluid Media (SFR) 142
B. Types of Derivatizations Used in SFE 144
C. Utilization of Catalysts with SFR 146
V. APPLICATIONS OF CRITICAL FLUIDS
FOR SAMPLE PREPARATION 149
A. Analysis of Trace Components 150
B. Proximate Fat Analysis 153
C. SFE Prior to Gas Chromatography (GC) 156
D. SFE with HPLC or SFC 158
E. SFE Integrated with Selected Chromatographic/
Spectroscopic Techniques (IR, MS) 164
VI. STATUS OF THE TECHNIQUE-CONCLUSIONS 166
REFERENCES 167
APPENDIX A 174
Sample preparation prior to chromatography has been an integral
step of analytical method development that has received increasing
emphasis in recent years. The rationale for this trend is the increas-
ing complexity of chemical analysis, which continues to place a
burden on the analyst using chromatographic methods. Hence
improvements in sample preparation prior to analysis via chromato-
graphic techniques can substantially reduce the complexity of such
assays as well as reduce the attrition on columns and associated
instrumentation. There are a plethora of sample preparation meth-
ods available, and this reviewwill focus the attributes of supercritical
fluids and similar compressed media as agents for this process.
