Synergistic effects of a zirconium doped stannate-carbon nitride nanocomposite on design of electrochemical sensor for sensitive detection of the antiandrogen drug flutamide

• Zr doping in SnO 2 (ZS) enhances charge carriers and active site availability. • New class of nanocomposite comprised of ZS and carbon nitride nanosheet (CN). • Correlative coupling between ZS and CN enabling efficient electron transfer. • ZS-CN nanocomposite based voltammetric sensor for flutamide monitoring. • Outstanding selectivity and sensitivity with robust stability and applicability. Flutamide (FLT), an anti-androgen drug widely used in anti-cancer therapy, can cause serious hepatotoxic side effects at high doses. However, released from industrial and hospital effluents, FLT is not fully removed by conventional water treatments, resulting in contamination of water sources that threatens aquatic ecosystems and thus human health. Therefore, there has been a pressing need for sensitive and reliable FLT monitoring, but existing techniques are often costly, labor-intensive, and complex, limiting their practicality. To address this challenge, herein we report the novel design of electrochemical sensor based on a new class of electrode modifier, ZS-CN nanocomposite, synthesized by integrating zirconium (Zr)-doped SnO 2 nanoparticles (ZS) onto 2D graphitic carbon nitride nanosheets (CN). Especially, we introduce Zr as a new dopant in SnO 2 and reveal that the correlative coupling of ZS with porous CN allows for their intimate interfacial contact that promotes efficient electron transfer and electrocatalytic activity, while keeping the functional groups of both components active. As a result, the electrochemical sensor designed by the ZS-CN nanocomposite coated glassy carbon electrode demonstrates an outstanding level of selectivity and sensitivity (1.6553 µA µM −1 cm −2 ) for FLT with a low detection limit (0.009 µM) and a wide detection linear range (0.04–1166 µM), alongside robust reproducibility, stability, and applicability in real-world samples (e.g., human urine and river water). Furthermore, its cyclic voltammetric responses provide mechanistic insights into the correlation between multi-electron redox process and FLT transformation pathways, informing future interfacial engineering strategies for designing versatile electrochemical systems for pharmaceutical pollutant monitoring.