Different types of hybrid nanocomposites were prepared from a copper-based metal-organic framework (MOF-199) and graphene (Gr) or fullerene (Fl). The porosity and quality of the nanocomposites were studied by scanning electron microscopy, transmission electron microscopy and BET surface area analysis. The nanocomposites are shown to be viable sorbents for the dispersive micro solid phase extraction of polycyclic aromatic hydrocarbons (PAHs) from environmental water samples. This is due to (a) the presence of MOF-199 which leads to improved adsorption capacity, and (b) the presence of Gr or Fl on the surface of MOF-199 which enhances the interaction with PAHs. Specifically, acenaphthene, anthracene, benz[a]anthracene, fluorene, naphthalene, 2-methylnaphthalene, and pyrene were studied. A comparison of the sorbents shows MOF-199/Gr to possess the highest adsorption affinity and to be most durable, probably a result of the high porosity of graphene. Following desorption with acetonitrile, the PAHs were quantified by GC with FID detection. Under the optimum conditions, limits of detection (at an S/N ratio of 3) range from 3 to 10 pg mL-1, and the analytical ranges are linear at 0.01-100 ng mL-1 of PAHs. The relative standard deviations for five replicates at two spiking levels (0.03 and 50 ng mL-1) range from 5.0 to 7.4%. The applicability of this method was confirmed by analyzing spiked real water samples, and recoveries are between 91.9 and 99.5%. Graphical abstract Different types of the hybrid nanocomposites of the copper-based metal-organic framework MOF-199 with graphene or fullerene were synthesized and used as sorbent for the dispersive micro solid phase extraction of polycyclic aromatic hydrocarbons in environmental water samples.
The stainless steel mesh, in the form of the disk, was coated with graphene oxide and poly(dimethylsiloxane) (GO-PDMS) by sol-gel technique. The coated stainless steel meshes are loaded in the mini-column as solid-phase extraction cartridge for the fast isolation and preconcentration of polycyclic aromatic hydrocarbons (PAHs) from real water samples. The extracted PAHs (naphthalene, acenaphthene, acenaphthylene, anthracene, benz[a]anthracene, fluorene, and pyrene) were quantified by gas chromatography-mass spectrometry. The operation parameters affecting the extraction efficiency including sample volume, desorption conditions, and ionic strength were investigated. At optimized conditions, the linearity of this method is obtained from 0.001 to 20 ng mL-1 with 0.2 to 1.0 pg mL-1 limit of detection. For 5 replicates at 3 spiking levels (0.1, 1, and 10 ng mL-1), the relative standard deviations between 4.0 and 6.3% were achieved. The absolute extraction recovery varied from 89.1 to 94.7%. The enrichment factors were in the range of 2227-2367. The method has been employed in the determination of PAHs in the real water samples including well water, tap water, river water, and wastewater. Relative recoveries are between 95.2 and 100.9%. Graphical abstractSchematic representation of the SPE procedure using the self-assembly SPE cartridge.