Microwave assisted extraction of organic compounds

Abstract

Microwave energy has been developed recently for the extraction of organic compounds from environmental matrices after its use in inorganic chemistry for trace metal analysis. The development in microwave techniques has occurred because of a need for a rapid, safe and cheap method. Conventional techniques for the extraction of solid matrices (such as Soxhlet) are time and solvent consuming and the analysis of numerous samples in environmental studies is limited by the extraction step. This review recalls the importance of the extraction step in the analytical procedure for the analysis of organic contaminants and the principles of extraction of solid matrices (sediment, soil, air particulate matter...). The theory of microwave heating is summarised and the microwave ovens used in analytical chemistry are described. Then, the review attempts to summarise all the studies about microwave assisted extraction for organic contaminants, on one hand in multimode microwave ovens in closed vessels and on the other hand in focused microwave ovens at atmospheric pressure. The microwave assisted extraction methods of volatile compounds are summarised. Finally, advantages of methods compared to conventional extraction are discussed.