Ionic liquid-coated Fe3O4 magnetic nanoparticles as an adsorbent of mixed hemimicelles solid-phase extraction for preconcentration of polycyclic aromatic hydrocarbons in environmental samples

In this paper, ionic liquid (IL)-coated magnetic Fe3O4 nanoparticles (NPs) as an adsorbent of mixed hemimicelles solid-phase extraction (SPE) was investigated for the preconcentration of polycyclic aromatic hydrocarbons (PAHs) from environmental samples. Due to the high surface area and excellent adsorption capacity of the Fe3O4 NPs after modification with ILs, satisfactory extraction recoveries can be achieved with only 80 mg Fe3O4 NPs, 50 mg IL, 300 mL solution at pH = 10 and 10 min for equilibration. A comprehensive study of the adsorption conditions such as the amount of Fe3O4 NPs and ILs, the solution pH, ionic strength, standing time, breakthrough volume, and desorption solvents was presented. The extraction ability of different coating agents, such as 1-hexadecyl-3-methylimidazolium bromide (C(16)mimBr), 1-decyl-3-methylimidazolium bromide (C(10)mimBr) and cationic surfactant cetyltrimethylammonium bromide (CTAB) was also compared. Under the optimized conditions, the recoveries for the water samples analysis were between 76 and 105% with relative standard deviations (RSDs) ranging from 3.9 to 6.9%, and the recoveries for soil samples were between 73 and 104% with RSDs ranging from 1.0 to 6.3%. In this method, only a small amount of C(16)mimBr (50 mg) and Fe3O4 NPs (80 mg) was needed to obtain satisfactory recoveries.