In-house metal-organic framework material for stir-bar sorptive extraction of acidic pharmaceutical compounds from environmental water samples

Pharmaceutical residues are increasingly recognized as emerging contaminants in aquatic environments due to their widespread consumption, improper disposal, and insufficient removal in wastewater treatment plants. These compounds, often found at trace levels, pose ecological risks owing to their bioaccumulation potential and biological activity. Micro-extraction techniques, especially stir-bar sorptive extraction (SBSE), have gained widespread use for their effectiveness in preconcentration and analytical applications. However, commercial SBSE coatings show limited retention of polar analytes and suffer from poor mechanical stability as well as high purchase cost. To address these limitations, this study presents the development and evaluation of an in-house hybrid coating material for SBSE with a total cost <5€/unit, based on metal-organic frameworks (MOFs) functionalized with amine groups that provide weak anion exchange (WAX) interactions. The performance of the amino-functionalized MOF attached to a glycidyl methacrylate-based monolith (GMA@NH₂-UiO-66(Zr)) was assessed for the extraction of acidic pharmaceutical compounds from environmental water samples, followed by determination using liquid chromatography-tandem mass spectrometry (LC-MS/MS). After the proper optimization, good analytical figures were obtained for river water samples, including the method’s limits of detection as low as 2 ng/L, adequate recoveries (22-41%), matrix effect between +9 and -2% and acceptable precision expressed as relative standard deviation below 25%. Once validated, the method was applied for the determination of acidic pharmaceuticals from environmental water samples, which were found at ng/L level. The new material exhibited improved retention of polar pharmaceuticals, high stability, and reproducibility, demonstrating its potential as an effective tool for environmental monitoring of pharmaceutical contaminants.