Direct Electrochemical Detection of Geosmin Using Zn₂Ti₃O₈ Nanosheets Grown on Graphene Oxide

The direct electrochemical detection of geosmin, a pervasive odor-causing compound in water, poses a longstanding analytical challenge owing to its exceptionally high oxidation potential. Here, we introduce a groundbreaking sensing architecture that achieves unprecedented direct anodic oxidation of geosmin using ultrathin, defective Zn₂Ti₃O₈ spinel nanosheets synthesized via a simple graphene oxide (GO)-confined growth. This innovative confined approach unexpectedly stabilizes a defective Zn₂Ti₃O₈ phase in a two-dimensional (2D) morphology, enabling superior charge transport and robust electrode-solution interfacial interactions. Integrated onto a glassy carbon electrode (GCE), the resulting platform dramatically lowers the overpotential for geosmin oxidation, circumventing the intrinsic limitations of conventional electrochemical sensors. Under optimized voltammetric conditions, the sensor delivers a linear dynamic range of 0.36-3.6 μg mL^-1, with limits of detection (LOD) and quantification (LOQ) of 0.08 and 0.27 μg mL^-1, respectively. The device exhibits excellent reproducibility, satisfactory recovery in spiked samples, and robust tolerance to common interferents. Beyond superior analytical metrics, this novel material establishes a simplified electrochemical approach for direct electrochemical monitoring of odorants in aqueous matrices, opening promising avenues for the design of affordable, portable sensors for real-time water quality assessment in field settings.