Green extraction approaches utilizing graphene and graphene oxide derivatives in environmental analysis

Green analytical chemistry emerged from green chemistry and is focused on the role of the analytical chemists in the development of novel environmental-friendly methodologies. In particular, sample preparation is the step of analytical methodologies that has gained more attention regarding the development of greener approaches, since this step requires the consumption of hazardous organic solvents. In order to reduce the adverse environmental impact of high organic solvent consumption, a plethora of green sample preparation techniques such as solid-phase microextraction (SPME), dispersive solid-phase extraction (d-SPE), magnetic solid-phase extraction (MSPE), and stir bar sorptive extraction (SBSE) have been developed. Moreover, in order to develop novel sample preparation methods with high extraction efficiencies, various novel materials have been studied. Among them, graphene and graphene oxide have gained a lot of attention in the last decade due to their benefits. Graphene is a carbonaceous material that consists of a single-layer or few-layer thickness of sp2-hybridized carbon atoms arranged in a honeycomb pattern. Graphene oxide exhibits a similar form with graphene; however, it is composed of a large number of groups that contain oxygen, and therefore, it exhibits higher polarity. These materials have been extensively studied for the extraction of organic compounds and metal ions, and they have proved to be powerful sorbents. In this chapter, we aim to discuss the applications of graphene- and graphene oxide-derived materials in environmental sample analysis for the determination of organic compounds and metal ions, while emphasis will be given in green sample preparation approaches.