Carboxylated Multiwalled Carbon Nanotubes as Dispersive Solid-Phase Extraction Sorbent to Determine Eighteen Polychlorinated Biphenyls in Vegetable Samples by Gas Chromatography-Mass Spectrometry

Table 2

Comparison of the proposed method with other methods reported in the literature for the determination of PCBs in vegetable samples.

Extraction	Cleanup	Detection	Volume of extraction solvent (mL)	Sample preparation time (h)	LOD (μg/kg)	Recovery	Reference
Soxhlet extraction	Concentrated sulfuric acid and silica gel/alumina column	GC-MS	—	>72	0.01	92.5 ± 8.5	[10]
UAE	C18 SPE	GC-MS	70	>12	1.43	80–87	[13]
UAE	Sulfuric acid-silica gel SPE	GC-ECD	120	>2.2	0.01–0.015	87	[40]
Mechanical shaking	Concentrated sulfuric acid	GC-ECD	≥150	>25.5	0.14–0.16 pg	75–85	[41]
Soxhlet extraction	Concentrated sulfuric acid and Florisil SPE	GC-MS	100	>22	0.04–0.43	87.5–106.8	[42]
UAE	MWCNTs-COOH d-SPE	GC-MS	10	<1.2	0.3–1.4	84.5–116.5	This work