New sorbents for extraction and microextraction techniques.

This review outlines recent progress in the research on some new classes of sorbents for extraction and microextraction techniques. Carbon nanotubes are allotropes of carbon with cylindrical structure. They are very stable systems having considerable chemical inertness due to the strong covalent bonds of the carbon atoms on the nanotube surface. Some applications of carbon nanotubes are presented in a perspective view. Molecular imprinting has proved to be an effective technique for the creation of recognition sites on a polymer scaffold. By a mechanism of molecular recognition, the molecularly imprinted polymers are used as selective tools for the development of various analytical techniques such as liquid chromatography, capillary electrochromatography, solid-phase extraction (SPE), binding assays and biosensors. Sol-gel chemistry provides a convenient pathway to create advanced material systems that can be effectively utilized to solve the solid phase microextraction fiber technology problems. This review is mainly focused on recent advanced developments in the design, synthesis and application of sol-gel in preparation of coatings for the SPME fibers. Copyright 2009 Elsevier B.V. All rights reserved.