Towards Safer Water: A Low‐Cost Disposable Electrochemical Sensor for Bisphenol A Using La 2 Sn 2 O 7 Nanostructures

ABSTRACT Bisphenol A (BPA), a widely used industrial chemical, persists in aquatic environments and poses serious endocrine‐disrupting risks to ecosystems and human health. This study presents a highly sensitive, selective electrochemical sensor using lanthanum stannate (La 2 Sn 2 O 7 ), a rare‐earth stannate, engineered for efficient BPA detection in real water matrices. The La 2 Sn 2 O 7 nanostructure was synthesized and employed as an electrocatalytic modifier, offering unique physicochemical properties that facilitate accelerated electron transfer kinetics and abundant electroactive surface sites. Systematic electrochemical characterizations confirmed the material's superior catalytic performance, attributable to its synergistic structural and electronic attributes. Under optimized pH and operating conditions, the La 2 Sn 2 O 7 ‐modified electrode demonstrated exceptional analytical capability, exhibiting an ultra‐low detection limit of 1.4 nM and a broad linear dynamic range spanning 0.001‒425.8 µ M . These findings indicate remarkable sensitivity and reliability in quantifying trace BPA levels. Moreover, the sensor demonstrated excellent analytical recovery and reproducibility in diverse real‐water samples, including lake, river, tap, and plastic‐bottled water, underscoring its robustness and practical applicability in complex environmental matrices. La 2 Sn 2 O 7 shows strong promise as an electrocatalyst, enabling real‐time BPA detection for enhanced environmental monitoring and public health protection in the field.