## 2 Hybrid Graphene-Based Materials (Hybrid GBMs)
### Graphene-Based Biosorbents
#### 2.5.2 Graphene-Based Materials Immobilized with Cyclodextrin  
CDs are oligopolysaccharides typically derived from starch through the enzymatic action of cyclodextrin glucanosyl transferase [24]. These molecules boast a distinctive structure characterized by a hydrophobic inner cavity and a hydrophilic surface, imparting remarkable physicochemical properties [73; 74]. Considering their sample preparation application, one of the main advantages of CDs is their unique shape and functionalization potential. [PERSON] et al. [65] CDs exhibit a cone-like structure reminiscent of hollow truncated cones, facilitating the encapsulation of guest molecules within their framework. Furthermore, the abundance of hydroxyl groups renders CDs ideal candidates for functionalization with various materials, enabling the creation of tailored sorbent phases [75]. When considering their role as sorbent phases, covalent bonding to solid supports bolsters the stability of cyclodext against water solubility challenges. Consequently, strategies for developing CD-based sorbents predominantly involve (I) immobilization onto inert supports, (II) integration with diverse nanomaterials, and (III) formation of nanosponges (NSs) through polymerization of cyclodext with an appropriate cross-linking agent [75; 76]. Regarding item II, coupling cyclodext with graphene-based materials has showcased significant promise in forging novel biosorbent phases. This combination amplifies the utility of graphene-based phases and expands their applicability across a spectrum of analytical strategies and complex sample evaluations [8]. The literature reports many synthesis approaches for obtention cyclodext with carbon-based materials. [PERSON] et al. [42] detailed the synthesis of a magnetic graphene oxide sorbent functionalized with \(\beta\)-cyclodextrin(in NiFe\({}_{2}\)O\({}_{4}\)@GO@\(\beta\)-CD), employed for the magnetic solid-phase extraction of bisphenols. In their method, the previously fabricated NiFe\({}_{2}\)O\({}_{4}\)@GO phase was combined with \(\beta\)-CD to create the ultimate sorbent phase. This resultant product showcased a substantial increase in specific surface area, attributed to the incorporation of \(\beta\)-CD, which enhanced the adsorption of the target analyte by host-guest interactions, such as hydrogen bonding and \(\pi\)-\(\pi\) interactions. Hybrid materials based on \(\beta\)-CD and GO have also been introduced to enhance the applicability of these materials and propose different synthesis strategies for their obtention. For example, [PERSON] and [PERSON] [24] reported the synthesis of \(\beta\)-cyclodextrin(in coupled to graphene oxide supported on aminopropyl silica (\(\beta\)-CD@GO@Sil). This synthesis involved using APTES combined with \(\beta\)-cyclodextrin(in for a subsequent reaction with graphene oxide and aminopropyl silica. The results showed that the final \(\beta\)-CD@GO@Sil material exhibited the adsorption characteristics typical of graphene-based materials. Furthermore, the selectivity of the material was attributed to the inclusion of \(\beta\)-cyclodextrin(in. The authors highlighted that supporting the material on aminopropyl silica opens new and unexplored horizons for applying graphene biosorbents in microextraction protocols. [PERSON] et al. [43] introduced an NS composed of polydimethylsiloxane/graphene oxide/\(\beta\)-cyclodextrin(in (PDMS/GO/\(\beta\)-CD) as a solid sorbent phase for detecting lavender essential oil. The fabrication of this NS involved three primary steps: preparing the PDMS sponge, modifying it with GO, and subsequently functionalities it with \(\beta\)-CD. In the penultimate steps, the polydimethylsiloxane/graphene oxide (PDMS/GO) sponge was derived through the amidation process of graphene oxide with polydimethylsiloxane/polydopamine/3-aminopropyltriethoxysilane (PDMS/PDA/APT), followed by solvent washing.