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Published Online: 15 SEP 2006
Copyright © 2000 John Wiley & Sons, Ltd. All rights reserved.
Encyclopedia of Analytical Chemistry
How to Cite
Luque de Castro, M. and Gámiz-Gracia, L. 2006. Pervaporation, Analytical. Encyclopedia of Analytical Chemistry. .
- Published Online: 15 SEP 2006
The use of pervaporation in analytical chemistry is a relatively new development. Pervaporation is a separation technique for the removal of volatile analytes or their volatile derivatives from the sample matrix. It can be defined as the integration of evaporation and gas diffusion in a single module. The volatile substances present in a heated donor phase evaporate through a porous membrane and the vapor condenses on the surface of a cool acceptor stream on the other side of the membrane. The temperature difference across the membrane is the driving force for the separation. An important characteristic of analytical pervaporation is the presence of a constant-volume air gap between the sample in the donor chamber and the membrane, which hinders any contact between them, thus avoiding clogging and/or deterioration of the membrane.
Pervaporation can also be used for sample pretreatment, e.g. for solid samples where leaching and derivatization of the analytes are done simultaneously. In this article, the applications of analytical pervaporation that have been developed so far are discussed. Special attention is paid to its use as an alternative to gas diffusion, to liquid samples containing solids in suspension and/or corrosive, to solid samples in which a single analyte must be determined, to multideterminations, and to speciation studies. The integration of this separation technique with detection and the coupling of a pervaporator to a gas chromatograph (GC), which constitutes a valid alternative to headspace sampling, is also commented upon.