Ergonomic and fully 3D-printed, activated, and modified electrochemical set-up for electroanalytical paracetamol detection.

In this work, we manufactured the entire electrochemical configuration (all electrodes along with the ergonomic cell), which was 3D-printed using fused deposition modelling (FDM) technology. All electrodes were printed from carbon black/poly(lactic acid) (CB/PLA) filament, while the cell body was produced with neutral PLA. An activation process was conducted to enhance the electrochemical properties of all electrodes (working electrode (WE), counter electrode (CE), and reference electrode (RE)), which included immersion in dichloromethane followed by anodic, and cathodic treatment. The WE was only subjected to the activation process, providing the best output when the synergistic action of organic solvent and electrochemical electrode surface treatment were used. The novel aspects of this work originate from the applied electrode surface treatment, adjustment of all three electrodes' placement in an ergonomic and fully 3D printed cell, and finally, RE and CE properties adjustment. For the latter, the REs properties were defined by electrodeposition of silver particles further covered with AgCl, providing a stable and constant reference potential. The CE was made out of 3D-printed CB/PLA modified with platinum particles, which enhanced its electric conductivity. Even though, in both cases, the surface coverage was found to be nonhomogeneous the electrodes displayed desired properties, creating cheap substitutions to commercially available components. All electrodes were comprehensively inspected with a range of characterization techniques, including voltammetry, chronoamperometry, electrochemical impedance spectroscopy, scanning electron microscopy, optical profilometry, attenuated total reflectance Fourier-transform infrared spectroscopy, laser-induced breakdown spectroscopy along with surface wettability studies. The electrochemical behavior of the system, in the presence of a model redox probe, ferrocenemethanol, was analyzed using cyclic voltammetry. Finally, our fully 3D-printed sensing platform was assessed for paracetamol determination giving the limit of detection and limit of quantification to be 0.38 μM and 1.26 μM, respectively. The system was successfully applied to the determination of paracetamol in a pharmaceutical tablet using the standard addition method, confirming its suitability for quantitative analysis in complex sample matrices.