Determination of polycyclic aromatic hydrocarbons in soil, tree leaves, and water samples by magnetic dispersive solid-phase extraction based on β-cyclodextrin functionalized graphene oxide followed by GC-FID

A high-performance sorbent was synthesized and used to extract some polycyclic aromatic hydrocarbons (naphthalene, acenaphthene, fluorene, phenanthrene, fluoranthene, pyrene, benzo[a]pyrene) from environmental samples by using magnetic dispersive solid-phase extraction (MdSPE) procedure followed by a gas chromatography-flame ionization detector (GC-FID). The sorbent was synthesized by grafting beta-cyclodextrin (beta-CD) onto magnetic graphene oxide (MGO) via hexamethylene diisocyanate (HMDI) as a linker. Prepared magnetic sorbent (MGO/HMDI/beta-CD) was characterized by Fourier transform infrared spectroscopy (FT-IR), the field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), the X-ray diffraction (XRD), vibrating-sample magnetometer (VSM), thermogravimetric analysis (TGA), and energydispersive X-ray spectroscopy. The variables that affect the performance of the extraction method were investigated in detail and thoroughly optimized using experimental design and response surface methodology. Under the optimum conditions (sorbent amount: 25 mg, extraction time: 20 min, concentration of NaCl: 27% (w/v), desorption time: 6 min, volume of desorption solvent: 300 mu L, and desorption solvent: toluene), enrichment factors were obtained between 46 and 62. The results indicated that the extraction recoveries of these compounds were in the range of 73.0-97.1%. Good linearity within the range of 5.0-1000.0 ng/mL with coefficients of determination higher than 0.984 was achieved. Detection limits were found to be 0.1-0.5 ng/mL, while the relative standard deviations (RSDs) were calculated to be <= 8.0% (n = 3). The fabricated sorbent was successfully applied for the extraction and quantification of PAHs in pretreated environmental samples (soil, tree leaves, and river water).