Reductive pathway profiling of chemical warfare agent simulant in complex matrices using hydrothermally engineered mixed-valent Y2NiMnO6 double perovskite

The detection of chemical warfare agent (CWA) simulants in complex matrices remains a critical challenge for safeguarding environmental and public health. In this study, we report the development of a highly sensitive and selective electrochemical sensor utilizing hydrothermally engineered Y₂NiMnO₆ (YNMO), a mixed-valent double perovskite, for the detection of paraoxon ethyl (PXE), a representative CWA simulant. The YNMO-modified glassy carbon electrode (YNMO/GCE) exhibited exceptional electrocatalytic performance, owing to the synergistic redox activity of Ni²⁺/Ni³⁺ and Mn³⁺/Mn⁴⁺ redox couples that significantly enhanced interfacial charge transfer kinetics. The sensor achieved an impressively low detection limit of 0.08 nM and a quantification limit of 5 nM, with a wide linear detection range spanning from 0.19 μM to 2147.51 μM. It demonstrated high analytical robustness, with excellent repeatability (relative standard deviation < 2.57 %), reproducibility (inter-electrode variation <1.7 %), and operational stability over a 30-day testing period. Notably, the sensor retained functionality under complex conditions, exhibiting strong anti-interference capability against structurally related organophosphates and coexisting environmental or biological species. Real-sample analyses in diverse matrices including river, pond, and tap water; synthetic saliva and sweat; and various food items yielded high recovery rates (98.6-101.8 %), confirming the sensor's practical applicability.