Pressurized liquid extraction of polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans and coplanar polychlorinated biphenyls from contaminated soil.

Extraction solvents for pressurized liquid extraction (PLE) used to extract polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans (PCDD/PCDFs), and coplanar polychlorinated biphenyls (Co-PCBs) from contaminated soil were investigated. The PCDD/PCDFs and Co-PCBs in Certified Reference Material: CRM 0422 (Forest soil) were extracted using toluene, n-hexane, acetone, acetone/toluene and acetone/n-hexane (1:1, v/v). Soxhlet extraction was the reference method. Results demonstrated that PLE using mixed solvents produced better analyte recoveries than the single solvents. However, these results were lower than those for Soxhlet extraction. Additional extraction cycles using mixed solvents achieved better recovery results. Mixed solvents and several extraction cycles were necessary for satisfactory extraction of more tightly bound PCDD/PCDFs and Co-PCBs from soil.