SELECTED APPLICATIONS OF THE USE OF SUPERCRITICAL FLUIDS IN COUPLED SYSTEMS

The gas-like mass transfer and liquid-like solvating properties of sup ercritical fluids, together with considerations on automation, speed a nd cost, make supercritical fluids very attractive for application in coupled systems. A number of coupled systems in which supercritical fl uids play a key role are described. Supercritical fluid extraction-cap illary gas chromatography-mass spectrometry (SFE-cGC-MS) has been appl ied to the determination of pesticides in fruit juices. For the determ ination of polycyclic aromatic hydrocarbons, triazines, chlorophenols and phenoxy acids in water samples, the SFE-cGC-MS system was extended with a sample preparation station after SFE, allowing the addition of internal standards and derivatization of the acidic solutes after SF extraction. The potential of on-line solid-phase extraction-supercriti cal fluid chromatography-diode array detection is illustrated with the determination of xanthines in iced tea and of traces of pesticides in water samples.