Layer-by-Layer Coating of Graphene Oxide on Fused Silica Fibers for Headspace Sampling of Nicotine in Hair Samples

The surface of a fused silica fiber was activated and coated with graphene oxide (GO) film, using a facile layer-by-layer coating strategy. PTES, (3-aminopropyl) triethoxysilane, was used as a covalent cross-linker for tight-binding of the GO layers. By the combination of GO sorption capacity and APTES cross-linking ability, the developed solid-phase microextraction (SPME) fibers exhibited a very good chemical/mechanical stability and high extraction efficiency. The developed fibers were used for headspace sampling of nicotine from the hair of smokers, without any sample preparation step. The determination of the analyte was done using GC-FID technique. Despite the thin thickness of GO multilayer, it was very robust and durable and its performance was higher than traditional GO coatings and polyacrylate commercial fibers. The most important experimental variables were studied. Under the optimal conditions, the limit of detection and relative standard deviation (RSD%, n=3) was 0.02 μg/g 5.6-8.9%, respectively. The calibration graph was linear over the range of 0.1-100 μg/g. The fiber was successfully applied for the determination of nicotine in hair samples of active and passive smokers.