Facile synthesis of polydivinylbenzene coated magnetic polydopamine coupled with pressurized liquid extraction for the extraction and cleanup of polycyclic aromatic hydrocarbons in soils

Due to the trace levels of polycyclic aromatic hydrocarbons (PAHs) in soil and the complexity of soil matrices, effective sample pretreatment methods are of great significance to obtain accurate analytical results. In this paper, polydopamine (PDA) encapsulated Fe3O4 particles were used as seeds for in situ polymerization of divinylbenzene (DVB) to derive magnetic hybrid material Fe3O4@PDA@PDVB. Coupled with pressurized liquid extraction, Fe3O4@PDA@PDVB was investigated as a selective adsorbent for the extraction and cleanup of PAHs in soil. The prepared magnetic material was characterized and demonstrated to possess strong hydrophobicity and superparamagnetism. Under optimal conditions, Fe3O4@PDA@PDVB can effectively extract 15 PAHs from a 30% methanol solution within 2 min, and it is more selective for PAHs than for n-alkane in soil extracts. The matrix effect significantly decreased after extraction by the prepared material, which showed superiority to a silica gel column method (EPA 3630C Method). The developed method was linear (5-1000 ng g(-1)) with coefficient of determination (R-2) ranging from 0.9986-0.9998, and the limits of detection were 0.13-0.54 ng g(-1). Additionally, repetitive experiments indicated that the prepared material was reproducible and reusable with relative standard deviations below 8.4% and 8.6%, respectively. Finally, the new method was successfully employed to determine the concentrations of PAHs in genuine soil and standard reference material, and the results were comparable to those of widely utilized EPA methodology. (C) 2019 Elsevier B.V. All rights reserved.