Electrostatic Assembly of Graphene@SiO2 Composite for Enhanced Dispersive Solid-Phase Extraction: Targeting Eight Pesticide Residues

As a new carbon nanomaterial, Graphene (Gr) has attracted wide attention in the field of separation and analysis because of its large specific surface area and strong hydrophobicity. A highly efficient and selective graphene/SiO₂ (Gr/SiO₂) dispersive solid-phase extraction (d-SPE) material was prepared through electrostatic assembly. This process involved the combination of negatively-charged poly (sodium 4-styrenesulfonate) (PSS) mediated GS (denoted as PSS-GS) and positively-charged SiO₂, modified with triethoxy silane amino. The precursor material was characterized using FESEM. We evaluated the extraction performance of this new sorbent with eight pesticide residues, using the HPLC-MS method. The sorbent demonstrated excellent recovery rates for the pesticide residues under various frequency of use conditions and pH levels. It showed that the SiO₂ and Gr have synergistic extraction effect, and the composite material has good stability and reusable, Ultimately, this newly developed d-SPE material was successfully applied in the analysis of fruit juice samples, yielding good recovery rates in the range of 82.18 to 117.49%.