Transition metal oxide-nanoengineered LIG e-tongue for discriminative analysis of phenolic compounds

Selective detection of phenolic compounds is imperative for environmental surveillance and public health safeguards. This study introduces a dual-electrode voltametric electronic tongue (e-tongue) leveraging transition metal oxide-nanoengineered laser-induced graphene (LIG) to resolve phenol and its cresol isomers (o-, m-, p-) despite overlapping electrochemical signals. Contrary to conventional single-electrode systems hindered by matrix-induced peak overlaps, our e-tongue employs a synergistic sensing arraying: MnO₂/LIG and Bi₂O₃/LIG. These composites are fabricated via a one-step in situ laser doping process, ensuring uniform nanoparticle integration while mitigating distributional inhomogeneity and interfacial weaknesses associated with post-synthetic modifications. Both MnO₂/LIG and Bi₂O₃/LIG exhibit augmented electroactive surface areas, conductivity, electron transport kinetics, hydrophilicity, and stability relative to pristine LIG. The dual-electrode system achieved robust differentiation of phenolics in buffered solutions, environmental water samples, and tobacco smoke matrices. This work pioneers a scalable nanoengineering strategy for multi-target analysis of structurally proximal pollutants, advancing point-of-need environmental monitoring technologies.