Abstract:
The rapid and reliable detection of toxic contaminants in food and cosmetic products remains challenging because of complex sample matrices and the need for scalable and high-performance electrode materials. Herein, a nanostructured laser-induced porous graphene (LIG) electrode was fabricated directly on a polyimide sheet through a simple, chemical-free single-step CO2 laser-writing process for the electrochemical detection of cadmium (Cd2+), lead (Pb2+), and paraquat (PQ) in two buffer electrolytes with single sensing platform. The laser-writing process generated a three-dimensional porous graphene architecture with interconnected conductive networks, structural defects, and oxygen-containing functional groups, collectively enhancing the electrochemically active surface area and facilitating rapid interfacial electron-transfer kinetics. Using square-wave anodic stripping voltammetry, the LIG electrode enabled simultaneous determination of Cd2+ and Pb2+ over a linear range of 1-6 mu M with detection limits of 43.7 and 29.69 nM, respectively. The proposed electrode exhibited satisfactory selectivity for Cd2+ and Pb2+ in the presence of potential interferents. For paraquat, the LIG electrode exhibited a linear response over the concentration range of 5-70 mu M with a detection limit of 0.21 mu M, together with good selectivity against the investigated ionic and molecular species, reproducibility, and satisfactory long-term stability. The LIG electrode enabled to recover the spiked Cd2+, Pb2+, and PQ in the extracted/digested food and cosmetic samples, using the standard addition method. These findings establish a clear structure-property-performance relationship, demonstrating that chemical-free laser-induced graphitization provides a scalable strategy for fabricating nanostructured graphene electrodes for electrochemical sensing applications in environmental and food safety monitoring.
