Robotic Plasma System for Rapid Activation of Mass-Produced Electrochemical Sensors
Marina Di-Oliveira, Mariana Marra, Raquel G. Rocha, Teodoro R. Terra, Rodrigo A.A. Muñoz, Eduardo M. Richter
Abstract
High Resolution Image Download MS PowerPoint Slide Polishing, cleaning, and activation of solid electrode surfaces are common in electrochemistry; however, they are often labor-intensive, operator-dependent, and poorly reproducible. In the context of large-scale production of disposable solid-state sensors, such as screen-printed electrodes (SPEs), traditional surface conditioning procedures have proven to be impractical and incompatible with automated workflows. Here, we report the development of a low-cost robotic system that integrates a Tesla coil-based air-plasma generator with a Python-controlled XY motion platform for rapid (∼15 s per 0.11 cm 2 ) and reproducible surface activation of SPEs. The main novelty of this study lies in the mechanization and reproducibility of the plasma activation process, achieved through the integration of a robotic platform with an air-plasma generator to enable standardized and scalable electrode conditioning. Morphological and Raman spectroscopic analyses revealed significant surface restructuring after plasma activation, leading to reduced charge-transfer resistance (from 7.10 to 0.45 kΩ), increased electron-transfer kinetics (∼4-fold increase in k 0 ), increased electroactive area (from 0.073 to 0.270 cm 2 ), and improved interelectrode reproducibility (RSD from 9.7 to 0.8%). The treatment also restored the voltammetric performance of carbon, gold, and platinum SPEs stored for over ten years. Plasma-treated carbon SPEs enabled the voltammetric determination of picric acid in simulated explosive samples (linear range: 0.5–50.0 μmol L –1; LOD: 0.1 μmol L –1 ). Moreover, 3D-printed electrodes were also successfully treated by using this system. This robotic plasma system provides a low-cost, scalable, and ecofriendly strategy for standardized activation of disposable electrodes, enhancing or restoring their electrochemical performance for routine analytical and industrial applications.