Applications of supercritical fluid extraction in multidimensional systems

Supercritical fluid extraction in plant essential and volatile oil analysis

The use of supercritical fluids, especially carbon dioxide, in the extraction of plant volatile components has increased during two last decades due to the expected advantages of the supercritical extraction process. Supercritical fluid extraction (SFE) is a rapid, selective and convenient method for sample preparation prior to the analysis of compounds in the volatile product of plant matrices. Also, SFE is a simple, inexpensive, fast, effective and virtually solvent-free sample pretreatment technique. This review provides a detailed and updated discussion of the developments, modes and applications of SFE in the isolation of essential oils from plant matrices. SFE is usually performed with pure or modified carbon dioxide, which facilitates off-line collection of extracts and on-line coupling with other analytical methods such as gas, liquid and supercritical fluid chromatography. In this review, we showed that a number of factors influence extraction yields, these being solubility of the solute in the fluid, diffusion through the matrix and collection process. Finally, SFE has been compared with conventional extraction methods in terms of selectivity, rapidity, cleanliness and possibility of manipulating the composition of the extract.

On-line hyphenation of supercritical fluid extraction and two-dimensional high performance liquid chromatography-atmospheric pressure chemical ionization tandem mass spectrometer for the analysis ofGanoderma lucidum

A novel on-line system combining supercritical fluid extraction (SFE) and two-dimensional high performance liquid chromatography (2D-HPLC) was developed. A trap column and two three-port valves were employed to couple SFE and 2D-HPLC system, which was composed of a CN column and a monolithic silica column, connected by a 10-port dual-position valve. The analytes extracted by supercritical CO2 were completely transferred to the 2D-HPLC system. After separation in two orthogonal modes, the eluents were delivered to APCI-tandem-MS for identification of the samples. In this way, sample preparation, separation, detection, and identification were integrated into an on-line system permitting analysis of the fruiting bodies of Ganoderma lucidum, and at least 73 components in the extract were resolved with calculated peak capacity of up to 1643.

Collection in analytical-scale supercritical fluid extraction

This review is a comprehensive summary of available collection techniques in supercritical fluid extraction (SFE), with emphasis on which parameters are especially important for a successful analyte collection. Environmental, biological and agricultural applications, including several types of sample matrices and analyte groups, are discussed with respect to choice of collection mode and optimization of collection conditions. This review also includes discussions about collection when a modifier is used or when the sample contains large amounts of fat or water, as well as possibilities to achieve enhanced selectivity.

Supercritical fluid extraction of pesticides in foods

This article summarizes research findings involving the supercritical fluid extraction (SFE) of pesticides in food and other tissue matrices. Emphasis is placed on multiresidue analysis of pesticides in nonfatty foods, including some previously unpublished aspects of SFE in this application. Brief overviews of pesticides and traditional multiresidue methods are given, followed by discussion of results for SFE applications in the pesticide residue analysis of foods.

Occurrence and determination of pesticides in natural and treated waters

Pesticides as environmental pollutants are described in detail along with their sources and paths of entry into various elements of the environment. Comprehensive literature data on the concentration of these pollutants in natural and treated waters and wastewaters are discussed. A wide selection of isolation and preconcentration techniques for these pollutants in water is presented and discussed. An emphasis is put on solid-phase extraction. In the case of the authors' work, a more detailed description is given.