Micro-solid phase extraction of some polycyclic aromatic hydrocarbons from environmental water samples using magnetic β-cyclodextrin-carbon nano-tube composite as a sorbent

Abstract

Previous studies have demonstrated the excellent capability of the cyclodextrins in pre-concentration of the organic pollutants from the aqueous solutions. In this work, β-cyclodextrin- multiwalled carbon nano-tube composite was produced from the reaction of oxidized carbon nano-tube with cyclodextrin in the presence of the hydrazine hydrate, and subsequently attaching this composite to the iron oxide nano-particles. Prepared magnetic nano-composite was characterized by the attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), the thermogravimetric analysis (TGA), the field emission scanning electron microscopy (FESEM), and the X-ray diffraction (XRD). This composite was applied to extract seven polycyclic aromatic hydrocarbons (PAHs) from the environmental water samples as follows: naphthalene, acenaphthene, fluorene, phenanthrene, fluoranthene, pyrene and benzo[a]pyrene. Analytes analysis was performed using the gas chromatography (GC) followed by the flame ionization detection (FID), and the predominant parameters influencing the extraction efficiency were investigated thoroughly. Under the optimized extraction conditions, the enrichment factor (EF) was ranging from 41.3 to 49.3 (EFmax = 50.0), and a suitable linearity was obtained (R2 = 0.992–0.997) within the range of 2.0–1000 ng/mL. The limits of the quantification and detection were 2.0–10.0 and 0.6–3.0 ng/mL, respectively. Finally, the synthesized magnetic sorbent and method were successfully utilized for the analysis of rain, well and agricultural water samples. The relative recoveries were ranging from 75.3–107.0% with an acceptable precision (5.5–8.3%) for PAHs extraction.