Around 20 g of a dry soil, sludge or cement sample and 10 g sodium sulfate are extracted with 100 mL n-hexane in a soxhlet extractor for 8 h. Then the extract is concentrated to a volume of 1-2 mL.

Conditioning: 2 mL n-hexane

Sample application: Slowly force or aspirate the extract of the sample through the column.

Elution: Aspirate 10 mL n-hexane slowly through the column.

Concentration: Concentrate to 5 mL.

Extraction: To gain a better peak shape in GC a subsequent acetonitrile extraction is performed. Extract 2 mL of the n-hexane extract with 2 mL acetonitrile. After phase partition use around 1 mL of the acetonitrile phase for GC analysis.