Disposable 3D-printed electrochemical sensor for in loco simultaneous monitoring of emerging pharmaceutical pollutants in aquatic ecosystems

The contamination of aquatic ecosystems with emerging pharmaceutical pollutants such as acetaminophen (AP) and 17β-estradiol (E2) is of global concern. For in loco analysis, a disposable miniaturized electrochemical sensor was fabricated by 3D printing conductive carbon black-polylactic acid (CB-PLA) filament onto an acrylonitrile butadiene styrene (ABS) platform. Electrochemical activation in alkaline medium promoted PLA saponification, exposing conductive CB sites. The effectiveness of this treatment was confirmed by electrochemical, microscopic, and spectroscopic techniques. Computational studies supported the adsorption mechanism of AP and E2 on the activated CB-PLA surface, with stronger interactions observed for E2. Calibration curves by square wave voltammetry were constructed for AP and E2 in concentration ranges of 0.50–25 and 0.75–50 μmol L⁻¹, respectively, with detection limits of 0.15 µmol L⁻¹ for AP and 0.23 µmol L⁻¹ for E2. The sensor was applied to in loco simultaneous determination of AP and E2 in water samples (freshwater, brackish, seawater) from Florianópolis, Brazil, a region of tourist and oyster and shellfish production. Statistical comparison with HPLC-DAD confirmed equivalent precision and accuracy. The sensor exhibited satisfactory repeatability, tolerance to common interferents, and reuse capability for up to three analyses. Coupled to a portable smartphone-operated potentiostat, the device proved to be a low-cost and practical tool for on-site environmental monitoring. Finally, greenness assessment by the AGREE metric (scoring 0.91) confirmed the environmentally friendly character of the method, reinforcing its potential as a sustainable alternative for screening emerging contaminants in aquatic ecosystems.