Silane modified nitrogen-doped graphene quantum dots as a high-efficiency hybrid sorbent for NSAIDs

Abstract

A hybrid sorbent material was developed by modifying nitrogen-doped graphene quantum dots (N-GQDs) with 3-glycidyloxypropyltrimethoxysilane (GPTMS) and 3-aminopropyltriethoxysilane (APTS), producing functionalized GQDs (f-GQDs) with enhanced extraction capabilities. Combining the adsorption properties of GQDs with the functional versatility of silanes, this material effectively serves as a solid-phase extraction sorbent for non-steroidal anti-inflammatory drugs (NSAIDs) from aqueous matrices. The f-GQDs composite was thoroughly characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), atomic force microscopy (AFM), and zeta potential analysis, confirming structural integrity and functional enhancements. The synergistic effects of silanes on the N-GQDs surface provided increased hydrophobicity and additional adsorption sites, resulting in superior extraction efficiency compared to conventional materials. Analytical parameters were optimized to yield maximum extraction performance, with the method showing excellent linearity (r² ≥ 0.99) over a concentration range of 50–500 μg L⁻¹, and low limits of detection (15.72–23.60 μg L⁻¹) and quantification (51.89–70.62 μg L⁻¹). High enrichment factors, recovery rates (95–98.7%), and reproducibility (RSDs < 10%, n = 3) demonstrate the robustness of this approach. Successfully applied to NSAID determination in an acetate buffer solution, this method is both efficient and sustainable, requiring minimal sorbent to achieve high extraction yields, showing strong potential for environmental and pharmaceutical analyses.