Fused silica beads coated with octadecylsilica nanoparticles as an efficient novel sorbent for solid-phase extraction of PAHs from water samples

Silica, as a plentiful natural material, is easily available and can be provided at low prices. It has a large surface area and great sorptive characteristics [1, 2]. However, these features can be enhanced by turning it into nano-configurations [3, 4]. Therefore, in this research, fused silica beads were coated by octadecylsilica nanoparticles (Nano-ODS) using a simple and eco-friendly nucleosynthesis reaction route, to create a high-surface area and remarkably efficient Si-Nano-ODS extraction phase [5]. The nanocomposite structure and morphology were characterized by FT-IR and SEM techniques. The modified beads were packed inside a cartridge and applied for solid-phase extraction (SPE) of polycyclic aromatic hydrocarbons (PAHs) in environmental water samples, followed by GC-FID determination. The sorbent showed a significant affinity for rapid adsorption of PAHs. The trapped analytes were then easily eluted with n-hexane/acetone (90/10). The effect of ionic strength, type and volume of eluent, flow rate of sample solution, and breakthrough volume, as the most important affecting experimental variables, were investigated. The accuracy of the method was also evaluated by the recovery of fortified samples. Good linearity’s were obtained for the calibration curves (R2 0.99) over the concentration range of 0.1-2000 ng g-1. The recoveries and relative standard deviations were found to be 82-104% and 7.8-14.6%, respectively. The developed Si-Nano-ODS-SPE-GC-FID method was successfully used for determination of PAHs in real water samples and satisfactory results obtained.