Thermo-responsive polymer tethered metal-organic framework core-shell magnetic microspheres for magnetic solid-phase extraction of alkylphenols from environmental water samples

• A thermo-responsive polymer tethered core-shell magnetic microspheres were synthesized.
• The microspheres were used as sorbent for MSPE of alkylphenols from water samples.
• High extraction efficiency was achieved using the developed method.

In this work, the thermo-responsive polymer PNIPAM tethered to Fe3O4@SiO2@MOF core-shell magnetic microspheres was first synthesized by a surface-selective post-synthetic strategy and underwent highly efficient magnetic solid-phase extraction (MSPE) of alkylphenols from aqueous samples. Alkylphenols, including 4-tert-octylphenol (OP) and 4-n-nonylphenol (NP), were selected as target compounds. The sample quantification was carried out using LC–MS/MS in multiple reaction monitor (MRM) mode. Under optimal working conditions, the developed method showed good linearity in the range of 5–1000 ng L−1, a low limit of detection (1.5 ng L−1), and good repeatability (relative standard deviation, <8%, n = 5) for NP and OP. Owning to the hydrophilic/hydrophobic switchable properties of the nanocomposite, high recoveries (78.7–104.3%) of alkylphenols were obtained under different extraction conditions. The levels of OP and NP in environmental samples collected from local river, lake and pond waters were analyzed using the developed method. It was believed that the synthesized material with the thermo-responsive coating, large surface areas and magnetic properties should have great potential in the extraction and removal of alkylphenols from environmental samples.