Coupled Supercritical Fluid Extraction-Capillary Gas Chromatography (SFE-GC)

Abstract

A frequently held misconception is that extracts resulting from supercritical fluid extraction (SFE) must be analyzed using supercritical fluid chromatography (SFC). While SFC is certainly useful for separating many analytes from SFE extracts, SFE is an independent sample preparation technique, and extracts can be analyzed using a wide variety of techniques including (but not limited to) chromatographic, spectroscopic, radiochemical, electrochemical, and gravimetric. When analytes have sufficient vapor pressures, capillary gas chromatography is the method of choice because of its very high resolution per unit time, and the excellent variety of detectors that are available. Since the most commonly used supercritical fluids (e.g., CO₂) are gases at ambient conditions, SFE can also be directly coupled with capillary GC (SFE-GC) using simple techniques.