## 2 Hybrid Graphene-Based Materials (Hybrid GBMs)
### Ionic Liquids  
ILs, composed of organic cations and inorganic anions, have been highlighted in sample preparation due to their unique properties, such as thermal and chemical stability, low volatility, and non-flammability ([PERSON] et al., 2018; [PERSON] et al., 2018; [PERSON] et al., 2018). Adjustable according to the choice of cations and anions, these liquids enhance the affinity and pre-concentration for various classes of analytes, improving sample cleanup through multiple interactions, including \(\pi\)-systems, hydrogen bonding, dispersive, electrostatic, and dipolar interactions ([PERSON] et al., 2018; [PERSON] et al., 2018). In this regard, several studies have employed different classes of ILs in combination with other sorbent materials in microextraction techniques. They have been serving various roles, such as functional monomers, cross-linkers, porogenic solvents, coating materials,  
Figure 2: Schematic of preparation procedure of GO-anchored silica composite. Reproduced with permission ([PERSON] et al., 2018) Copyright © 2024 Elsevier. and, in some cases, even magnetic components, depending on their class [52]. Previously, ILs were used as alternatives to volatile organic solvents in liquid-liquid extractions (LLE) and elution solvents in SPE [49; 50]. However, due to the toxicological potential of certain IL combinations and their persistence in aquatic and terrestrial environments, the use of small amounts of ILs as sorbent modifiers in solid-based sample preparation techniques appears to be a more environmentally viable option, as they are stable and highly reusable [50]. Nevertheless, functionalizing graphene derivatives with ILs makes the sorbent more stable. It helps to overcome problems such as the aggregation of its nanosheets, especially in dispersive extraction techniques in aqueous media. Furthermore, it increases the absorption capacity of the sorbent and reduces its loss during extractions [22; 25; 51]. [PERSON] et al. [13] developed an ionic liquid-thiol-graphene oxide composite (IL-TGO) that exhibited high extraction capacity for the pesticide fipronil, surpassing other commercial sorbents. The covalent functionalization of graphene oxide with 1-Allyl-3-pentafluorobenzyl imidazole bromide (PFBr) through intermediate thiol groups allowed hydrophobic and hydrogen interactions as well as the creation of new interaction sites through the IL. The stability of the sorbent enabled its reuse in over fifteen extraction cycles in chicken egg samples using a combined solid-phase microextraction technique. In addition to particulate sorbents, the use of ILs for monolith preparation has also been recently reported. [PERSON] et al. [25] prepared an aerogel using natural chitosan supported on GO layers through covalent bonds (IL-CS-GOA). Additionally, they added the ionic liquid--1-allyl-3-methylimidazolium tetrafluoroborate ([AMIm]BF4)--as a porous and modifier, increasing the surface area of the sorbent, resulting in a porous three-dimensional aerogel for extracting polyhalogenated carbazoles from sediment samples. The authors reported that this combination of materials resulted in a high specific surface area of 173 m\({}^{2}\) g\({}^{-1}\), attributed to the addition of the IL. The sorbent was employed in a glass dropper extraction system, with just 8 mg showing a reusability rate of six cycles and recovery values above 80%, demonstrating its high adsorption capacity and efficient mass transfer for the analytes. In the field of magnetic ionic liquids (MILs), [PERSON] and collaborators [32] described the synthesis of magnetized graphene oxide nanoparticles with trihexyl([tetradecyl])phosphonium hexachlorodysprosiaet(III) ([P6; 6; 6; 14]3 DyCl6) (GO@MIL) sorbent, using the dispersive solid-phase microextraction technique (DuSPE) to extract inorganic antimony from water and food samples.