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

Abstract

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 (C₁₆mimBr), 1-decyl-3-methylimidazolium bromide (C₁₀mimBr) 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 C₁₆mimBr (50 mg) and Fe₃O₄ NPs (80 mg) was needed to obtain satisfactory recoveries.