Microwave assisted solvent extraction MASE

MASE utilises electromagnetic radiation to desorb organics from their solid matrices. MASE typically operates at 2.45 GHz. The use of a microwave oven for sample preparation originates from inorganic or elemental analysis. In this case the electromagnetic radiation is used to destroy inorganic and organic matter using a combination of strong acids and peroxides. The first application of microwaves for the extraction of organics from solid material appeared in 1986 [30]. In recent years, different systems have become commercially available and they are based on extraction in a closed high pressure vessel with microwave absorbing solvents, extraction with a non-microwave absorbing solvent in an open vessel and/or extraction with a non-microwave absorbing solvent in a closed vessel applying a Weflon stir bar that heats the solvent. The performance of MASE has been compared to other recently introduced techniques like ASE and SFE and similar recoveries were obtained for soil and sediment samples [31]. For food analysis, the same disadvantages mentioned for ASE apply namely lack of selectivity and the dilution effect. Moreover, care should be taken with solutes that are thermolabile or can rearrange under the influence of electromagnetic radiation. The performance of MASE has also been evaluated for the Belgian dioxin crisis (Section 3.1.6).

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