## 1 Introduction  
Chemical agents pose a significant threat to human safety [1; 2]. They could be categorized as incapacitating agents, which diminish people's fighting abilities without long-term effects, and lethal agents, which can even kill humans [3]. Figure 1 illustrates the structures of Lewisite (L), O-ethyl S-2-disopropylaminoethyl methylphosphonothioate (VX), Sarin (GB), and Soman (GD), which are confirmed lethal agents. These agents typically attack the respiratory system or the skin [4]. VX, GB, and GD inhibit the activity of the cholinesterase enzyme, leading to severe damage to the central nervous system [5]. Moreover, these agents are highly soluble in water or organic solvents, causing harm even at extremely low concentrations [6]. Despite the Chemical Weapons Convention (CWC) which came into effect in 1997, chemical agents continue to threaten civilian and military populations due to their destructive capacity [7]. The concealment of chemical agents usage and the difficulty of detecting residual agents in the environment underscore the importance of developing reliable traceable detection methods. Such methods are crucial for providing evidence of chemical weapons and improving medical treatment for poisoned individuals [8]. To enhance the extraction and enrichment of chemical agents for retrospective detection, the adsorbent used in sample preparation should be well-designed, easy to use, insensitive, and posing no additional safety concerns. Previous studies had employed various materials such as activated carbon [9; 10; 11], metal oxide nanoparticles [12; 13; 14; 15; 16; 17], and metal-organic framework structures (MOFs) [18; 19; 20; 21] for chemical agents and simulant adsorption. For example, [PERSON] et al. [22] used chitosan-derived porous activated carbon to remove the simulant agents for chemical weapons, achieving a saturation adsorption capacity of approximately 412 mg-g\({}^{-1}\) carbon after 2 days. [PERSON] et al. [23] utilized a co-precipitation method to prepare zinc-iron and copper-iron mixed (hydr) oxides, finding that the zinc-iron samples exhibited higher activity than the copper-iron samples when exposed to surrogates for 5 days. However, the adsorption capacity of these materials, especially within a relatively short timeframe, still need to be improved. Graphene oxide (GO) has garnered significant attention in recent decades due to its unique properties. GO is highly oxidized graphite with abundant oxygen-containing functional groups (-OH, -COOH, -CHO, and -COC-) on its surface [24; 25; 26]. It shares a similar high surface area to graphene, and the high surface-to-volume ratio of GO offers benefits in adsorption, including rapid equilibrium rates [27; 28; 29; 30]. [PERSON] et al. [31] prepared TiO\({}_{2}\) nanoparticles supported on GO flakes and studied their adsorption properties for the simulant agents, highlighting the importance of GO in increasing surface area and improving adsorption capacity. [PERSON] et al. [32] demonstrated a simple low-temperature water-based method to create a novel nanocomposite, GO@MnO\({}_{2}\), and evaluated its adsorption activity with nerve agent simulants, achieving an almost complete degradation of dimethyl methyl phosphonate (DMMP) and triethyl phosphate (TEP) within 2 h. Additionally, GO showed great potential as an adsorbent for sample preparation. However, these materials were a challenge to prepare and separate from solutions during experiments [33]. An effective approach was to employ magnetic solid-phase extraction (MSPE). Magnetic (Fe\({}_{3}\)O\({}_{4}\)) was widely used in MSPE due to its high magnetic moments, small size, biocompatibility, and ease of preparation [34]. With the assistance of Fe\({}_{3}\)O\({}_{4}\), the separation of the sorbent (GO) from the sample was easily achieved by applying an external magnetic field, significantly reducing separation time compared to centrifuging or filtering methods [33; 35].