Selective Extraction of Organic Contaminants from Soil Using Pressurised Liquid Extraction

Table 5

Amount of PAHs and sterols (𝜇g/kg) extracted from native contaminated soil and recoveries (%) of PAHs and sterols from spiked soil using optimum PLE conditions with silica (5 g) inside the extraction cell and without silica using EPA Method 3545.

Compound	Native contaminated soil (𝑛=3)		Spiked soil (𝑛=3)
	With addition of silica in ASE extraction cell^a	EPA method; 3545^b	With addition of silica in ASE extraction cell^a	EPA method; 3545^b
Naphthalene; Acenaphthalene; Acenaphthene; Fluorene; Pyrene; Benzo[a]anthracene; Benzo[a]pyrene; Coprostanol; Cholesterol; Stigmasterol; Stigmastanol; 𝛽-Sitosterol	1746.2 (6.0); 770.0 (28.7); 1630.8 (0.8); 1674.5 (2.9); 851.3 (5.0); 1867.5 (19.7); 2266.2 (13.2); 1888.8 (17.0); 4067.6 (21.3); 2397.5 (20.0); 1517.1 (8.1); 8169.0 (8.7)	1999.9 (12.0); 968.4 (20.4); 1399.0 (3.6); 1666.7 (11.4); 821.8 (4.4); 2136.3 (43.1); 2029.6 (10.6); 2215.4 (15.0); 3135.6 (23.1); 2037.0 (14.3); 2074.1 (34.3); 7599.2 (19.7)	78.4 (7.2); 90.1 (9.6); 96.7 (12.6); 104.1 (4.5); 99.3 (12.0); 94.2 (5.8); 92.0 (6.0); 95.7 (7.9); 97.0 (7.5); 123.9 (12.0); 99.1 (6.7); n.a	77.4 (10.2); 91.4 (5.8); 95.2 (3.2); 105.3 (3.5); 102.8 (9.4); 122.0 (9.5); 133.6 (32.7); 96.6 (2.2); 104.7 (3.3); 275.4 (6.2); 96.6 (3.3); n.a

^a5 g silica packed in the cell; PLE parameters: 125°C, 1400 psi, 10 min (optimum conditions); solvent: (1st extraction: 𝑛-hexane, 2nd extraction: methanol).
^bPLE parameters:100°C, 1500 psi, 5 min (EPA Method 3545); solvent: DCM [14].
n.a: not available (not tested).
Relative standard deviation (in parentheses).
Note: chlorpyrifos, phenol, and pentachlorophenol were not included.