Ionic liquid coated magnetic core/shell Fe3O4@SiO2 nanoparticles for the separation/analysis of linuron in food samples

• A new method of magnetic solid phase extraction (MSPE) coupled with UV spectrometry for separation/analysis of linuron.
• Linuron adsorbed rapidly on Fe3O4@SiO2@[OMIM]PF6 and eluanted by ethanol.
• Preconcentration factor of the proposed method was 10-fold.
• This method has been successfully applied to the determination of linuron in real samples.

Three hydrophobic ionic liquids (ILs) including 1-butyl-3-methylimidazole hexafluorophosphate ([BMIM]PF6), 1-hexyl-3-methyl-imidazole hexafluorophosphate ([HMIM]PF6), and 1-octyl-3-methylimidazole hexafluoro-phosphate ([OMIM]PF6) coated Fe3O4@SiO2 nanoparticles with core–shell structure to prepare magnetic solid phase extraction agent (Fe3O4@SiO2@ILs) and establish a new method of magnetic solid phase extraction (MSPE) coupled with UV spectrometry for separation/analysis of linuron. The results showed that linuron was adsorbed rapidly by Fe3O4@SiO2@[OMIM]PF6 and eluanted by ethanol. Under the optimal conditions, preconcentration factor of the proposed method was 10-fold. The linear range, detection limit, correlation coefficient (R) and relative standard deviation (RSD) were found to be 0.04–20.00 μg mL−1, 5.0 ng mL−1, 0.9993 and 2.8% (n = 3, c = 4.00 μg mL−1), respectively. The Fe3O4@SiO2 nanoparticles could be used repeatedly for 10 times. This proposed method has been successfully applied to the determination of linuron in food samples.

Fe3O4@SiO2@ILs with adsorbed target linuron was separated from the solution by an external magnetic field. The residual linuron in the supernatants was determined by UV–vis at 246 nm. Elinuron% was gradually increased with the loaded IL cation alkyl chain growth and Elinuron% on Fe3O4@SiO2@[OMIM]PF6 showed the highest extraction efficiency.Figure optionsDownload as PowerPoint slide