On-line supercritical fluid extraction-capillary gas chromatography

Abstract

A new analytical methodology combining on-line supercritical fluid extraction with high-resolution capillary gas chromatography for automated sample preparation and analysis is described. Analytical-scale supercritical fluid extraction utilizes the variable solvating power of a supercritical fluid to selectively extract and isolate discrete fractions from a sample matrix. The supercritical fluid extract is decompressed through a restrictor to deposit and concentrate the analytes at the inlet of a standard capillary gas chromatography column for subsequent analysis. This methodology allows several modes of operation including quantitative extraction of all analytes from a sample matrix, quantitative extraction and concentration of trace analytes, selective extractions at various solvating powers to obtain specific fractions, or multiple-step extractions at various pressures for qualitative characterizations. This initial report describes the later two modes of operation and demonstrates the potential usefulness of this methodology for sample extraction and selective fractionation using a standard polycyclic aromatic hydrocarbon mixture and two complex sample matrices.