Magnetically mixed hemimicelles solid-phase extraction based on ionic liquid-coated Fe3O4 nanoparticles for the analysis of trace organic contaminants in water
Ionic liquid (IL)-coated magnetic Fe3O4 nanoparticles (NPs) as an adsorbent of mixed hemimicelles solid-phase extraction (SPE) are proposed for the preconcentration of five organic contaminants (catechol, bisphenol A, 2,4-dichlorophenol, 1,3,5-trichlorobenzene and acrylonitrile) from environmental water sample prior to high-performance liquid chromatography (HPLC). In the present study, mixed hemimicelles formed by IL-coated Fe3O4 NPs showed a great adsorptive tendency towards the target analytes, and then the analyte-adsorbed mixed hemimicelles could be readily isolated from the sample solution by a magnet. Note that the proposed method could greatly simplify the operation and reduce the whole pretreatment time. Moreover, several parameters affecting extraction efficiency, such as the amount of Fe3O4 and [C8MIm]Br IL, the type and pH of desorption solvent, and the extraction time and salt effect, were investigated. Under optimum conditions, satisfactory recoveries for the target analytes were in the range of 90%–102% with 3.3%–8.1% relative standard deviations (RSD, n = 6), 90%–111% with 2.1%–7.6% RSD, 92%–99% with 5.5%–13.5% RSD at 0.01 μg mL−1, 0.1 μg mL−1 and 100.0 μg mL−1 levels, respectively. The limits of detection (LODs) for the target analytes were in the range of 0.01–0.07 μg L−1.