Hybrid nanocomposites prepared from a metal-organic framework of type MOF-199(Cu) and graphene or fullerene as sorbents for dispersive solid phase extraction of polycyclic aromatic hydrocarbons

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%.

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