One-pot synthesis of magnetic adsorbents with integrated pH regulation for convenient and rapid determination of non-steroidal anti-inflammatory drugs in plasma

Abstract

This work introduces a magnetic nanocomposite created via a one-pot method to produce a magnetic adsorbent with built-in pH regulation capabilities, optimizing the extraction and analysis of non-steroidal anti-inflammatory drugs (NSAIDs) in biological samples. The adsorbent material was prepared by mechanically integrating three key components: Fe₃O₄ nanoparticles for magnetic separation, hydroxylated multiwalled carbon nanotubes (MWCNTs-OH) for enhanced adsorption capacity, and citric acid (CA) serving as an intrinsic pH modulator. The synthesized material exhibits exceptional properties, including an extensive surface area and rapid magnetic response, facilitating the selective capture of the target analyte. A distinctive feature of this system is its ability to self-regulate the extraction environment to achieve optimal acidity, thereby eliminating manual pH adjustments and significantly simplifying pretreatment procedures. When coupled with high-performance liquid chromatography with ultraviolet detection (HPLC-UV) analysis, the composite demonstrated high extraction efficiency—with extraction recoveries ranging from 57.12 % to 78.56 % for five NSAIDs—and sensitive quantification of NSAIDs in human plasma. Validation studies revealed satisfactory method performance with good linear correlation (R²>0.99), acceptable accuracy, and reproducible precision. Successful application to clinical specimens confirmed the practical utility of this approach. This integrated methodology represents a significant advancement in sample preparation technology, offering an efficient and economical solution for therapeutic drug monitoring, with promising applications in clinical diagnostics and pharmaceutical research. • A one-pot magnetic adsorbent with integrated pH regulation was synthesized. • Citric acid in the composite enables automatic acidification during extraction. • The method enables rapid MSPE of NSAIDs from plasma without pH adjustment. • High extraction efficiency and reproducibility were achieved using HPLC-UV. • The approach simplifies therapeutic drug monitoring of NSAIDs in biofluids.