Novel laser-engineered graphene electrodes from low-cost polyether sulfone membranes for the sensitive chemoselective sensing of bioactive molecules.

High-performance electrodes based on carbonaceous nanomaterials are pivotal for several electrochemical applications that require interfaces with enhanced kinetics. In this study, we report an innovative approach to develop composite membranes for producing laser-engineered graphene electrodes (LEGEs) for electrochemical sensing. Composite membranes were prepared by blending aminated polyethersulfone (H₂N-PES) with carbon black (CB) at different weight ratios (0.1, 0.2, and 0.3 wt%). The resulting composite membranes served as scaffolds for preparing LEGEs. Both the composite membranes and the derived LEGEs were thoroughly characterized using spectroscopic, thermal, electrochemical, and scanning electron miscroscopy techniques. The results showed that the incorporation of CB into the polymer substantially enhanced the electrochemical performance compared to the pristine H₂N-PES membrane, particularly for the membrane containing 0.3 wt% loading of CB; it can be used for ascorbic acid determination in the concentration range of 10–300 µM with a detection limit of 2.45 µM, with high selectivity over uric acid and dopamine. LEGEs were successfully applied for the selective electrochemical sensing of ascorbic acid in spiked solutions and in commercial orange juice samples.