Selective Extraction of Organic Contaminants from Soil Using Pressurised Liquid Extraction

Table 2

Amount of silica used to perform selective extraction of PAHs and sterols from soil samples.

Compound	Amount of silica
	10 g		5 g		4 g		3 g		1 g
	% Recovery (RSD %); (𝑛=3)
	^a1st	^b2nd	1st	2nd	1st	2nd	1st	2nd	1st	2nd
Naphtalene; Acenaphtalene; acenaphthene; Fluorene; Pyrene; Benzo[a]anthracene; Benzo[a]pyrene; Coprostanol; Cholesterol; Stigmasterol; Stigmastanol	83.2 (9.0); 87.2 (12.4); 87.8 (9.5); 94.8 (3.3); 91.3 (5.1); 67.4 (10.0); 58.3 (2.4); nd; nd; nd; nd	nd; nd; nd; nd; nd; 31.2 (4.8); 28.3 (3.4); 103.3 (7.2); 103.9 (0.6); 99.6 (5.8); 99.3 (3.3)	87.1 (8.8); 91.6 (11.2); 94.2 (2.1); 94.2 (3.4); 96.2 (2.8); 90.9 (10.4); 91.4 (13.2); nd; nd; nd; nd	nd; nd; nd; nd; nd; nd; nd; 100.5 (2.1); 100.2 (11.1); 97.5 (3.0); 93.7 (5.0)	94.9 (7.2); 92.9 (7.1); 95.4 (9.2); 100.2 (8.8); 99.7 (2.9); 97.5 (7.2); 94.7 (12.8); 12.1 (2.5); 5.9 (3.9); nd; 6.9 (1.7)	nd; nd; nd; nd; nd; nd; nd; 87.0 (5.6); 90.9 (5.5); 101.0 (2.5); 91 (4.8)	92.0 (4.1); 100.4 (7.9); 94.4 (4.3); 86.3 (5.0); 87.9 (8.8); 93.3 (2.8); 94.5 (4.0); 23.4 (3.4); 16.8 (2.7); nd; 18.5 (2.1)	nd; nd; nd; nd; nd; nd; nd; 81.0 (1.4); 90.9 (4.4); 98.5 (0.4); 79.7 (3.9)	87.5 (4.9); 95.6 (3.8); 95.5 (2.7); 95.9 (4.4); 99.6 (3.4); 95.3 (6.7); 99.1 (3.4); 52.8 (12.7); 20.7 (21.3); 25.6 (15.6); 33.2 (21.4)	nd; nd; nd; nd; nd; nd; nd; 40.2 (18.6); 60.8 (3.1); 66.9 (5.1); 51.7 (7.7)

^a1st: first extraction (𝑛-hexane).
^b2nd: second extraction (MeOH).
Note: chlorpyrifos, phenol, and pentachlorophenol were not included in this experiment.