This study presents a rapid, environmentally friendly, and scalable activation method for 3D-printed poly-(lactic acid)/carbon black (PLA/CB) electrodes using atmospheric air plasma under ambient conditions. The goal was to optimize the plasma activation time and compare its efficiency with conventional activation techniques using N,N-dimethylformamide (DMF) and sodium hydroxide (NaOH). Surface morphology, chemical composition, wettability, and electrochemical performance were systematically evaluated through scanning electron microscopy (SEM), Raman spectroscopy, XPS, contact angle measurements, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). Plasma treatment, as short as 5 s, effectively removed the PLA matrix from the electrode surface, enhanced surface roughness, hydrophilicity, and exposure of conductive carbon black particles, leading to increased electrochemical performance. Compared to chemical activation, 40 s of plasma activation yielded comparable performance with significantly shorter processing times (vs NaOH) and without hazardous solvents (such as DMF). Finally, the activated electrodes were successfully applied in the development, optimization, and validation of a novel electrochemical protocol for the determination of the antihypertensive drug amlodipine, revealing high sensitivity, a low limit of detection of 0.09 μM, precision (RSD of 6.6%), and recovery (97.1 and 105.4%) in pharmaceutical formulations. The findings demonstrate the promising potential of air plasma activation as a sustainable and efficient approach for preparing 3D-printed electrodes for analytical and sensing applications.

• Publikační typ
• časopisecké články MeSH

Background: Gas sensors are very important in several fields like gas monitoring, safety and environmental applications. In this approach, a new gas sensing concept is investigated which combines the powerful adsorption probability of metal oxide conductive sensors (MOS) with an optical ellipsometric readout. This concept shows promising results to solve the problems of cross sensitivity of the MOS concept. Results: Undoped tin oxide (SnOx) and iron doped tin oxide (Fe:SnOx) thin add-on films were prepared by magnetron sputtering on the top of the actual surface plasmon resonance (SPR) sensing gold layer. The films were tested for their sensitivity to several gas species in the surface plasmon resonance enhanced (SPREE) gas measurement. It was found that the undoped tin oxide (SnOx) shows higher sensitivities to propane (C3H8) then to carbon monoxide (CO). By using Fe:SnOx, this relation is inverted. This behavior was explained by a change of the amount of binding sites for CO in the layer due to this iron doping. For hydrogen (H2) no such relation was found but the sensing ability was identical for both layer materials. This observation was related to a different sensing mechanism for H2 which is driven by the diffusion into the layer instead of adsorption on the surface. Conclusion: The gas sensing selectivity can be enhanced by tuning the properties of the thin film overcoating. A relation of the binding sites in the doped and undoped SnOx films and the gas sensing abilities for CO and C3H8 was found. This could open the path for optimized gas sensing devices with different coated SPREE sensors.

• Klíčová slova
• doped tin oxide, ellipsometry, gas sensing, surface plasmon resonance, thin films, transparent conductive oxides,
• Publikační typ
• časopisecké články MeSH