ORIGINAL PAPER 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 Razieh Zakerian 1 & Soleiman Bahar 1 Received: 1 May 2019 /Accepted: 17 September 2019 # Springer-Verlag GmbH Austria, part of Springer Nature 2019 Abstract 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 tech- nique 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 μgL -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. Keywords Adsorbent . Polycyclic aromatic hydrocarbons . Electrochemical exfoliation . Graphene . Coating . Headspace SPME . Gas chromatography . Real sample . Flame ionization detection Introduction Solid phase microextraction is one of the common methods for sample preparation. It was introduced by Pawliszyn et al. as a suitable alternative to the traditional sample preparation methods and offers various advantages [1]. Since no solvent is used in this method or little amounts of organic solvents are required, SPME is used as an acceptable method of analyzing environmental, pharmaceutical, and food samples. This is be- cause of the integration of the sampling and sample prepara- tion into one step, the ease of use, the low cost, and online process of this method [2–4]. The efficiency of SPME with respect to the extraction capa- bility, selectivity, and repeatability, strongly depends on the prop- erties of the extraction phase which is also known as the absor- bent phase. Although, various commercial fibers are currently available, these fibers are not diverse enough. In addition, other limitations related to using these fibers are the low thermal and chemical stability along with high cost and the short lifetime of fibers. Hence, producing new types of fibers has been one of the most important recent challenges to the researchers. Various types of fiber coatings with different substances have been intro- duced. Ionic liquids/polymeric ionic liquids, molecularly imprinted polymers, metals, nanostructured metal oxides (NMOs), and carbonaceous materials are some examples of fiber coatings which could be used for this purpose [ 5–8]. Graphene is used as coating in SPME fibers mainly because of its large special cross-section, considerable thermal and chem- ical stability, great mechanical power, ability to establish π–π interactions and its affinity to organic compounds. Several methods for preparation of graphene have been developed. These methods include scotch-tape isolation, [9] epitaxial growth, [10] bottom-up synthesis from aromatic precursors, Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00604-019-3851-5) contains supplementary material, which is available to authorized users. * Soleiman Bahar s.bahar@uok.ac.ir 1 Department of Chemistry, Faculty of Science, University of Kurdistan, P.O. Box 416, Sanandaj, Islamic Republic of Iran Microchimica Acta (2019) 186:861 https://doi.org/10.1007/s00604-019-3851-5