## 1 Introduction  
Since the confirmation of the existence of graphene (G), a single-layer carbon allotrope, in 2004 [1, 2], this material has stood out in various areas, such as energy generation, electronics, sensors, and other material science fields, due to its unique properties, such as flexibility, lightness, thermal and electrical conductivity, and mechanical resistance to high pressures [3, 4]. In addition to these, some peculiar characteristics of this nanomaterial, such as its extensive surface area, its binding sites arranged in a \"honeycomb\" pattern, the presence of delocalized \(\pi\) electrons, and its single-layer structure, among others, have prompted investigation of its use as a sorbent in sample preparation techniques, with the earliest records dating back to the early 2010s [5, 6, 7]. Among the various methods for obtaining graphene, such as mechanical or chemical exfoliation from graphite, pyrolysis, and chemical vapor deposition (CVD), the most widely used method in the field of sorbent preparation is chemical synthesis or chemical reduction from graphene oxide (GO) [8]. GO is the precursor to graphene obtained from the oxidation of graphite, a step in which the Hummers methodology is often used and has undergone modifications over the years to improve the process. The single-layer structure of GO is very similar to that of graphene (Figure 1), except for the presence of oxygen-containing functional groups, such as epoxy, hydroxyl, and carboxyl, protruding from the nanosheetobtained through a change in the hybridization of carbon atoms from sp\({}^{2}\) to sp\({}^{3}\), imparting this derivative with a hydrophilic characteristic and enabling interaction with compounds containing more polar groups. Finally, after obtaining GO, a reducing agent is used to reduce the oxygenated groups of GO, resulting in reduced graphene oxide (rGO), which exhibits properties very similar to graphene, such as high hydrophobicity, albeit with different chemical structures [9]. In this context, especially in solid phase-based extraction techniques, there has been an increasing demand for sorbents with enhanced selectivity, i.e., those that promote efficient interactions with various analytes in the same sample, providing a less costly method aligned with the principles of green analytical chemistry (GAC) [10; 11]. Thus, GO, in particular, allows for chemical functionalization with other components, such as ionic liquids (ILs) [12; 13], silica derivatives [14; 15], magnetic materials [16; 17], molecularly imprinted polymers (MIPs) [18; 19], resins [20], deep eutectic solvents (DESs) [21; 22], and carbon-based biosorbents [23; 24; 25], among other materials. These materials are typically obtained through covalent bonding with oxygenated groups, resulting in hybrid materials promoting multiple interactions with the analytes and improving method performance, even in complex matrices [26]. Notably, modified graphene-based materials (GBMs) have been widely and successfully utilized in solid phase-based extraction techniques in conventional and miniaturized formats, with applications across various matrices, including biological, food, beverage, and environmental samples [27]. Their versatile applications underscore the importance of evaluating the methods' efficiency, the phases' selectivity, and the ecological effects they may cause. Several aspects, such as the toxicity of reagents and solvents used in synthesis and extraction methods, the quantity of sorbent and its potential for reuse, energy consumption, waste generation, sample consumption, and the volume of organic solvents used, need to be considered to minimize the environmental impact of each extraction process. Following this brief introduction, this study aims to provide an overview of the literature on using modified GBMs in miniaturized solid-phase sample preparation techniques over the past seven years (from 2018 to May 2024).