Magnetic solid phase extraction using gold immobilized magnetic mesoporous silica nanoparticles coupled with dispersive liquid–liquid microextraction for determination of polycyclic aromatic hydrocarbons

• A novel nanocomposite was utilized by gold coating of magnetic MCM-41.
• The present sorbent was coupled with dispersive liquid–liquid microextraction procedure.
• The proposed method was developed for trace analysis of some polycyclic aromatic hydrocarbons.

An efficient magnetic sorbent was introduced for solid phase extraction by incorporation of the gold nanoparticles into the hexagonal lattice of magnetic MCM-41. For the effective incorporation of the gold nanoparticles, magnetic MCM-41 was functionalized with 3-aminopropyltriethoxysilane (APTES), which then interacted with Au atoms through the amine groups. Furthermore, to achieve high pre-concentration factors (PFs), the method was coupled with dispersive liquid–liquid microextraction (DLLME) procedure. Polycyclic aromatic hydrocarbons (PAHs) were used as the model compounds to evaluate the extraction performance of the proposed method. The π-system of PAH compounds and immobilized Au atoms on the surface of the sorbent can cause the electron donor–acceptor interactions. The parameters affecting extraction recovery such as types of the disperser and extraction solvents, pH of the sample solution, and the extraction time were optimized. Under the optimized conditions, the high PFs were obtained in the range 5519–6271 for the target analytes. The kinetic adsorption illustrated that 5 min was sufficient to achieve adsorption equilibrium for PAHs. The evaluations also showed a linearity range 0.01–50 μg L−1 with the detection limit in the range 0.002–0.004 μg L−1 for the PAHs. The applicability of the method for the analysis of PAHs in real samples was justified by the extraction of PAHs from seawater samples. The results indicated good recovery efficiencies ranging from 91.4 to 104.2%.