Magnetic nanoparticles coated with ionic liquid for the extraction of endocrine disrupting compounds from waters

A hybrid nanomaterial was synthesized to be used in dispersive solid phase microextraction. It consist of a magnetic core (Fe3O4), obtained by coprecipitation covered by a silica (SiO2) layer were the ionic liquid methylimidazolium hexafluorophosphate (MIM-PF6) was attached. The Fe3O4@SiO2@MIM-PF6 nanoparticles have been characterized by microscopy and X-ray diffraction. The chemical composition of the hybrid nanoparticles has been studied by infrared spectroscopy and thermogravimetrical analyses. Finally, its potential in dispersive microextraction was evaluated for the isolation of 11 endocrine disrupting compounds (benzophenones, bisphenol A and parabens) from water samples. For this purpose, 10 mg of the Fe3O4@SiO2@MIM-PF6 are added to 100 mL of water sample (pH = 8, NaCI 30% w/v) dispersed by ultrasound (1 min) and vortex stirring (20 min). Next, an external magnet is used to recover the MNPs. Later, the analytes are eluted from MNPs with 500 mu L of methanol under ultrasonic irradiation. 5 mu L of the extract is finally injected into a liquid chromatograph with tandem mass spectrometric detection (HPLC-MS/MS) for analytes separation and quantification. The proposed microextraction method allows the determination of the target compounds with limits of detection in the range from 0.16 to 1.21 mu g/L and the linearity was maintained between the limits of quantification and 500 mu/L. The precision, expressed as relative standard deviation was better than 8.3%. The recovery study was performed on different water samples obtaining percentages higher than 87%, which demonstrated the applicability of the hybrid sorbent for the selected analytical problem. Moreover, the proposed method provides enrichment factors in the range from 15.4 to 49.2. Butylparaben, benzophenone 3 and benzophenone 6 were detected in the swimming pool water samples analyzed following the proposed microextraction method. The simultaneous presence of analytes from different endocrine disrupting families reveal the need for methodologies including a wider variety of compounds than those currently available. (C) 2016 Elsevier B.V. All rights reserved.