Dynamic microwave-assisted extraction

An apparatus for extraction of solid matrices has been constructed which ut ilizes a microwave technique for heating in a dynamic mode. During the extr action, fresh solvent is continuously pumped through the extraction cell, w hich is maintained at a slight overpressure in order to keep the solvent in a liquid state. The extraction efficiency, which can be easily monitored, has been investigated in a factorial design and validated for polycyclic ar omatic hydrocarbons in a reference sediment sample (EC-I). Important parame ters were found to be temperature and duration of extraction. Flow-rate had no significant first-order effect on the recovery, but interaction effects with flow-rate were found to be significant. The dynamic microwave-assiste d extraction apparatus was demonstrated to yield recoveries equivalent to S oxhlet extraction, but in a much shorter time. Each extraction of EC-1 typi cally takes 40 min. (C) 2000 Elsevier Science B.V. All rights reserved.