Electrochemical exfoliation of pencil graphite for preparation of graphene coating as a new versatile SPME fiber for determination of polycyclic aromatic hydrocarbons by gas chromatography.

A graphene coating was prepared through electrochemical exfoliation of pencil graphite and then used as a fiber coating for headspace solid-phase microextraction of polycyclic aromatic hydrocarbons (PAHs) from water samples by GC analysis technique with flame ionization detector since flame ionization detector work according to the principle of ions released in the combustion of the sample species if there are any organic compounds. The graphene layers were produced by applying an anodic voltage of +2 V to the pencil graphite electrode in 1 M sulfuric acid solution as an electrolyte. The adsorbent was characterized by using scanning electron microscopy. Following thermal desorption, the PAHs (specfically naphthalene, acenaphthene, fullerene, phenanthrene, anthracene and fluoranthene) were quantified by GC. Under optimum conditions (extraction temperature, 65 °C; extraction time, 35 min; salt concentration of 20% w/v; desorption temperature, 260 °C; desorption time, 5 min), the limits of detection range between 10 and 90 ng L-1, and the linear ranges extend from 0.05-50 μg L-1. The repeatability of the extraction process and the fiber-to-fiber reproducibility were in the ranges of 4.3-0.2% and 7.3-9.8%, respectively. Graphical abstractSchematic representation of electrochemical exfoliation of pencil core to prepare a headspace solid phase microextraction (HS-SPME) graphene fiber coating. After applying a voltage, the graphene nanosheets thus produced are used for determination of polycyclic aromatic hydrocarbons (PAHs) in water samples.