A Fast and Simple Ozone‐mediated Method towards Highly Activated Screen Printed Carbon Electrodes as Versatile Electroanalytical Tools

Laser-Treated Screen-Printed Carbon Electrodes for Electrochemiluminescence imaging

Electrochemiluminescence (ECL) is nowadays a powerful technique widely used in biosensing and imaging, offering high sensitivity and specificity for detecting and mapping biomolecules. Screen-printed electrodes (SPEs) offer a versatile and cost-effective platform for ECL applications due to their ease of fabrication, disposability, and suitability for large-scale production. This research introduces a novel method for improving the ECL characteristics of screen-printed carbon electrodes (SPCEs) through the application of CO2 laser treatment following fabrication. Using advanced ECL microscopy, we analyze three distinct carbon paste-based electrodes and show that low-energy laser exposure (ranging from 7 to 12 mJ·cm-2) enhances the electrochemical performance of the electrodes. This enhancement results from the selective removal of surface binders and contaminants achieved by the laser treatment. We employed ECL microscopy to characterize the ECL emission using a bead-based system incorporating magnetic microbeads, like those used in commercial platforms. This approach enabled high-resolution spatial mapping of the electrode surface, offering valuable insights into its electrochemical performance. Through quantitative assessment using a photomultiplier tube (PMT), it was observed that GST electrodes could detect biomarkers with high sensitivity, achieving an approximate detection limit (LOD) of 11 antibodies per μm2. These findings emphasize the potential of laser-modified GST electrodes in enabling highly sensitive electrochemiluminescent immunoassays and various biosensing applications.

On the performance of carbon-based screen-printed electrodes for (in)organic hydroperoxides sensing in rainwater

Hydroperoxides play important roles in atmospheric chemical processes since they act as strong oxidants. This paper details with the modification, characterization and performance of different carbon-based screen-printed electrodes to develop a sensor that allows to analyze organic and inorganic hydroperoxides in atmospheric samples. Commercial electrodes made up of graphite, graphene, carbon nanotubes and graphene oxide were electrochemically activated and subsequently modified by layer-by-layer method with a conducting polymer of azure-A and electrodeposited platinum nanoparticles. Characterization of modified electrodes was performed by FE-SEM, XPS, Raman spectroscopy, cyclic voltammetry, and impedance spectroscopy. Even though all modified carbonaceous substrates enabled the development of competitive electrochemical sensors for (in)organic hydroperoxides detection, carbon nanotubes underlying substrate exhibited the best performances in terms of sensitivity, stability, limit of detection and linear range. This amperometric sensor displayed linear responses to hydroperoxides over 0.081-450 μM with detection limits in the range of 24-558 nM and sensitivity values among 0.0628±1.6E-4 and 0.0112±0.71E-4 μA/μM for the different hydroperoxides herein studied. The developed electrochemical sensor was successfully applied to the analysis of (in)organic hydroperoxides in rainwater samples. Measurements in rainwater were performed in a city located in the East of Spain and collected at two different sites (downtown and suburban area) on two different dates (July and November 2020). The presented results demonstrated high sensitivity and selectivity for the detection of hydroperoxides among a plethora of substances naturally present in rainwater.