The application of core-shell materials as packing materials for liquid chromatography columns is common in analytical chemistry, however their use as sorbents in solid-phase extraction (SPE) is surprisingly underexplored. In the present study, core-shell polymer microspheres with strong cation-exchange character were designed and synthesized. These new materials benefit from having hypercrosslinked and relatively thin functional shells, which raises the specific surface areas and sorption capacities of the sorbents and allows for relatively shorter diffusion path lengths for analytes. The core-shell polymer microspheres were evaluated as SPE sorbents for the extraction of basic pharmaceuticals from environmental water samples. Following optimization of the pH and volume of the loading solution, as well as optimization of the loading step, the SPE method was validated in terms of apparent and relative recoveries, matrix effect, limits of detection and quantification and precision. The method yielded very promising results in terms of apparent recoveries (>39%) and matrix effect (<±29%) and was applied successfully to the determination of basic pharmaceuticals in environmental water samples (river water, effluent wastewater and influent wastewater)
