3D-printed removable-cap device with embedded magnet for magnetic solid phase extraction

BACKGROUND: Magnetic adsorbents are widely employed in sample preparation, but magnetic solid-phase extraction (MSPE) still faces limitations related to magnet handling and pipetting, which increase time, variability, and operational costs. To overcome these drawbacks, we developed a 3D-printed magnetic removable-cap extraction device aimed at simplifying manipulation, improving reproducibility, and minimizing solvent consumption in the extraction step. As a proof of concept, a restricted-double-access magnetic polypyrrole adsorbent was synthesized, characterized, and applied to the extraction of nifedipine (NDP) and nimodipine (NMDP) from human plasma prior to chromatographic analysis. RESULTS: , respectively, and protein removal reached 93%. The magnetic adsorbent was reusable for up to three extraction cycles without loss of performance. SIGNIFICANCE: Coupling the 3D-printed device with the magnetic adsorbent enabled efficient, selective, and reproducible determination of NDP and NMDP in human plasma while minimizing sample handling and solvent use. Green analytical metrics confirmed this workflow as an eco-friendly, rapid, and reliable alternative for bioanalytical sample preparation.