Development of a 3D-Printed PLA Composite Stir-Bar-Based Extraction Method for Emerging Contaminants

Emerging contaminants (ECs) are increasingly detected in aquatic environments, raising concerns due to their persistence and potential human health risks. In parallel, the need for greener sample-preparation approaches aligned with White Analytical Chemistry principles has stimulated the development of solvent-free, low-cost extraction tools [1]. 3D printing enables rapid production of customized biodegradable extraction devices using polylactic acid (PLA) and composite filaments [2,3]. In this work, three 3D-printed PLA-based materials—neat PLA, carbon-fiber-reinforced PLA (CF-PLA), and wood-fiber-reinforced PLA (WF-PLA)—were fabricated by fused deposition modelling as disks and magnetic stir bars and evaluated for the extraction of more than 40 ECs from acidified saline water samples, followed by LC–MS/MS analysis. All PLA-based devices showed strong affinity toward hydrophobic analytes, with relative peak-area decreases above 90% for UV filters. In contrast, polar compounds were generally poorly extracted, and acidic drugs and PFAS exhibited low recoveries with neat PLA. CF-PLA consistently showed higher extraction capability than neat PLA, confirming the contribution of carbon fibers to hydrophobic interactions. WF-PLA devices displayed extraction behavior comparable to the other PLA materials but provided improved recoveries for PFAS and azithromycin and measurable extraction of some more polar ECs (e.g., naproxen). These results indicate that incorporation of wood fibers can enhance interactions with selected polar contaminants [4,5]., although the effect appears partially limited, probably due to the fiber embedding within the PLA matrix. WF-PLA magnetic stir bars were produced in-house at very low cost and demonstrated a potentialities for the effective extraction of both apolar ECs and selected polar compounds. A desorption step using organic solvents was preliminarily assessed and showed promising efficiency. In addition, a controlled partial degradation of the PLA matrix is being investigated to progressively expose embedded wood fibers while preserving device integrity, with the aim of further improving the extraction of polar ECs. [1] Nowak et al., TrAC, 2021. [2] Scaffaro et al., Polym. Test., 2024. [3] Mestre-Manrique et al., Adv. Sample Prep., 2023. [4] Godiya et al., Environ. Chem. Lett., 2025. [5] Olorunnisola et al., Carbohydr. Polym., 2023.