In situ preparation of core-shell magnetic porous aromatic framework nanoparticles for mixed-mode solid-phase extraction of trace multitarget analytes.

This study reports a novel strategy for the preparation of porous aromatic framework (PAF-6) coated magnetic nanoparticles (PAF-6 MNPs) using cyanuric chloride as a planar trigonal basis upon which to build a linear piperazine linker unit. The PAF-6 MNPs were examined as an efficient solid-phase extraction (SPE) sorbent for enrichment of trace organic pollutants including phenol, 2,4,6-trinitrophenol, naphthalene, naphthol, bisphenol A, 2,4-dichlorophenol and 3-nitrochlorobenzene in water. The high-performance liquid chromatography detection limits of such analytes were in the range of 0.08-5.02 ng/mL and recoveries were found to be 84.0-94.0% in well water, tap water, river water and wastewater. The main toxic components of cigarette smoke, including phenolic compounds and benzo[a]pyrene, are efficiently adsorbed by PAF-6 MNPs, and over 50% of such toxins are removed. Theoretical computations were performed to understand the molecular interaction mechanism between PAF-6 and such analytes. The results demonstrate that the PAF-6 MNPs sorbents show excellent adsorption of phenols, polycyclic aromatic hydrocarbons and nitroaromatics based on multiple π-π stacking and hydrogen-bond interactions. These results suggest that the PAF-6 MNPs can be applied to extraction, removal and determination of diverse trace multi-target analytes from complex media.