Polydopamine-assisted attachment of β-cyclodextrin onto iron oxide/silica core-shell nanoparticles for magnetic dispersive solid phase extraction of aromatic molecules from environmental water samples.

Pollution monitoring in a contaminated environmental water samples is a big challenge. In this article, immobilization of β-cyclodextrin molecules onto the magnetic core-shell silica nanoparticles was conducted by using adhesive properties of polydopamine. The synthesis path was included of three steps: producing Fe3O4 nanoparticles as a core, coating the cores with a silica layer, and further coating with β-cyclodextrin molecules. The structural characteristics of the synthesized nanocomposite were investigated by using attenuated total reflection-Fourier transform infrared spectroscopy, x-ray diffraction analysis, field emission scanning microscopy, transmission electron microscopy, dynamic light scattering, vibrating-sample magnetometer and energy-dispersive X-ray spectroscopy. Afterwards, obtained nanocomposite was used to extract eight polycyclic aromatic hydrocarbons from environmental water samples. Results were demonstrated that analyts with different chemical structures had different extraction manners during the process. Important effective parameters on the extraction efficiency; such as sorbent type and mass, desorption solvent (type and volume), salt concentration and the time of extraction & desorption; were investigated. Under the optimum operating conditions, good linearity within the range of 1-1000 ng/mL was obtained while coefficient of determination (r2) was in the range of 0.990-0.998. The limits of detection were between 0.04 and 0.57 ng/mL, and the enrichment factor was found to be 21-90. This nanocomposite was also applied for the extraction and enrichment of aromatic analytes from the canal and rain water samples prior to gas chromatography analysis.