Fabrication of a three-dimensional graphene coating for solid-phase microextraction of polycyclic aromatic hydrocarbons

A novel three-dimensional graphene (3D-G) coated fiber for solid-phase microextraction (SPME) was fabricated via a sol-gel coating method on stainless steel wires. The 3D-G was obtained by connecting graphene oxide (GO) sheets with Ca2+ and water molecules by hydrothermal treatment. Due to the pi-pi stacking and hydrophobic interactions between the 3D-G and the analytes, the 3D-G fibers showed high extraction efficiencies for the polycyclic aromatic hydrocarbons (PAHs). The developed method, which combined the 3D-G coated fiber-based SPME with gas chromatography-flame ionization detection, had large enhancement factors (842-2458), low limits of detection (2.0-10.0 ng L-1) and good linear range (10.0-1000.0 ng L-1) for the PAHs in water samples. Single fiber repeatability and fiber-to-fiber reproducibility were in the range of 4.7-8.8% and 6.4-11.9%, respectively. The recoveries of the analytes for the method were in the range from 76.5% to 102.6%. The fiber exhibited an excellent durability and can be reused more than 150 times without a significant loss of the extraction performance. The method was successfully applied to the determination of PAHs in water and soil samples.