Magnetic porous aromatic framework with a core-shell structure as a sorbent for rapid extraction of phenols and their quantitation in urine by HPLC-UV.

A porous aromatic framework (PAF) is shown to be a viable sorbent for the adsorption of phenols. To overcome the difficulty of quick adsorption and enrichment by phenols from the matrix, a sorbent material consisting of porous aromatic framework magnetic nanoparticles (PAF MNPs) with a core-shell structure was fabricated by an in situ growth method. The PAF MNP sorbent was characterized by transmission electron microscopy, Fourier transform infrared spectroscopy and other techniques. The factors affecting enrichment performance including the amount of PAF-6 MNPs, sample pH, extraction time and elution conditions were optimized. Under the optimal conditions, a method utilizing high-performance liquid chromatography with an ultraviolet detector (HPLC-UV) was developed to quantify phenols in urine. The method showed good linearity (r ≥ 0.998), good precision (RSD ≤ 9.9%, n = 6) and a low limit of detection (1.0-2.0 ng/mL, S/N = 3), with recoveries performed in urine matrix ranging from 76.7% to 113.2%. The method is simple, time-saving and sensitive. Moreover, compared with traditional mass spectrometry detection methods, this method has advantages in terms of low cost and repeatability. Graphical abstract.