A graphene based bucky gel-coated stainless steel fiber was prepared and applied to headspace solid phase microextraction of volatile organic compounds. Graphene was mixed with an ionic liquid to produce a bucky gel that displays the attractive features of both compounds. It can be directly deposited on an etched stainless steel wire to give the fiber for use in extraction of benzene, toluene, ethylbenzene and xylene (BTEX) isomers. The presence of graphene favors the π-interaction between the sorbent and aromatic analytes. The sorbent is thermally stable up to 300 °C and can be used more than 50 times. It was characterized by field emission scanning electron microscopy, FT-IR spectroscopy and thermogravimetric analysis. Under optimized conditions, linear responses were found in the range of 0.11-5000 μg L-1 for toluene, 0.15-5000 for benzene and o-xylene, 0.17-5000 for m- and p-xylene and 0.20-5000 for ethylbenzene. Limits of detection are between 0.03 and 0.06 μg L-1 (at an S/N ratio of 3). The run-to-run RSDs are <5.8% (for n = 6), and fiber-to-fiber RSDs are 4.1-9.2% (n = 4). The method was successfully applied to the extraction of BTEX isomers in spiked urine samples and gave recoveries between 88 and 105%. Graphical abstract Graphene based bucky gel (G-BG) was prepared by mixing an ionic liquid with graphene. It was physically deposited on stainless steel wire. The fiber was applied to the headspace solid phase microextraction (HS-SPME) of benzene, toluene, ethylbenzene and xylenes.
Keywords: BTEX; Carbon nanomaterials; Fiber fabrication; Ionic liquid; Nanofluid; Physical deposition; Soft material; Urine samples.