COMPARISON OF PRESSURIZED LIQUID EXTRACTION WITH SOXHLET EXTRACTION FOR THE ANALYSIS OF POLYCHLORINATED DIBENZO-P-DIOXINS AND DIBENZOFURANSFROM FLY-ASH AND ENVIRONMENTAL MATRICES

Dynamic high-pressure solvent extraction is a new, rapid and solvent-s aving extraction technique for performing pressurised liquid extractio ns. The technique uses conventional solvent or mixtures of solvents fo r the extraction of solid material under elevated temperature and pres sure. A continuous flow of fresh solvent during the extraction provide s for a high extraction efficiency, short extraction times and low sol vent consumption. The extraction device and the optimisation of the ex traction procedure shall be described. For demonstrating the applicabi lity of this technique, polychlorinated dibenzodioxins and -furans wer e extracted from different matrices which include fly ash, filter dust , and soil. Soxhlet extractions were performed as a reference method. The comparative results show that dynamic high-pressure solvent extrac tion provides extraction efficiencies equal to, or even higher, than S oxhlet. (C) 1998 Elsevier Science B.V. All rights reserved.