Treatment with CO₂ laser in SPE with Two Working Electrodes for Electrochemical Detection of Propranolol

Recent advancements in conductive inks, multiplex systems, and innovative treatments have enhanced electrochemical sensor functionality. In this context, lab-made screen-printed electrodes (SPEs) offer a cost-effective alternative to conventional electrodes, with various treatments improving their analytical performance. CO₂ laser-scribing, a low-cost pyrolysis method, converts organic substrates into conductive materials, improving conductivity and performance. In this study, a dual working-electrode SPE was fabricated and treated via CO₂ laser-scribing. Optimizing laser power, Z-distance, and scan rate led to significant increases in current magnitude and electroactive area. Morphological analysis using scanning electron microscopy and contact angle measurements confirmed a new conductive layer with greater thickness and hydrophobicity, likely carbon-based. The laser-treated SPE enabled sensitive detection of propranolol (PRNL), a β -blocker banned in sports. Using differential pulse voltammetry, the sensors exhibited a linear range from 5.0 to 1000 μmol l −1 , with limits of detection of 0.98 and 1.00 μmol l −1 . Recovery in tap water ranged from 95.6% to 109%. This study highlights the potential of CO₂ laser-treated SPEs for PRNL detection in environmental and real-sample contexts.