Recent advances in the coupling of carbon dioxide-based extraction and separation techniques

Any successful analytical method results from a flawless combination of at least three major steps, consisting of sample preparation, instrumental analysis, and data processing. Apart from selectivity and effectiveness, speed and cheapness obviously represent desirable features of any analytical methods and, to this regard, the use of carbon dioxide as a supercritical fluid offers unique opportunities for extraction and separation, with reduced time and solvent consumption. In this review, recent progresses in hardware and column technology for the on-line coupling of supercritical fluid extraction (SFE) and chromatography (SFC) are presented, and major applications developed in the last two decades are illustrated and critically discussed. The basic principles of carbon dioxide-based techniques are preliminarily summarized in brief, in order to make the reader acquainted with both theoretical and instrumental concerns, as well as with the advantages to be gained from the on-line hyphenation of SFE and SFC.