Environmentally relevant monitoring of pendimethalin in soil and water samples using a surfactant-assisted antimony (III) oxide nanorods and multi-walled carbon nanotubes hybrid nanomaterial-engineered sensor

초록

Pendimethalin (PND), a prevalent dinitroaniline herbicide, poses significant environmental and health risks due to its persistence, bioaccumulation and potential carcinogenicity. Here, we present a novel voltammetric sensor integrated using surfactant-assisted antimony (III) oxide (Sb2O3) nanorods and multi-walled carbon nanotube (MWCNT) hybrid nanocomposites for sensitive and selective PND detection. The nanocomposite was synthesized via a simple sonication-assisted method that ensured homogeneous dispersion of Sb2O3 nanorods on a conductive MWCNT matrix, as confirmed by field-emission scanning electron microscope, transmission electron microscope, energy dispersive X-ray spectroscopy, powder X-ray diffraction, Raman and X-ray photoelectron spectroscopy analyses. The strong Sb-O-C interfacial coupling and defect-engineered carbon framework enhanced electron transport and electrochemical activity. When modified onto a screen-printed carbon electrode (SPCE), the Sb2O3@MWCNT/SPCE exhibited superior electron transfer kinetics, low charge-transfer resistance and high electrochemically active surface area. The sensor demonstrated a wide linear range (0.01-75 mu M), a low detection limit (2.23 nM) and remarkable selectivity toward PND, even in the presence of structurally similar herbicides and pesticides. Notably, the sensor exhibited excellent repeatability, reproducibility and stability under optimized conditions. Particularly, it enabled real-time monitoring of PND degradation under simulated environmental conditions and achieved recovery rates of 92.0-107.1 % in soil and river water samples. This work represents the first report of an Sb2O3@MWCNT-based electrode for herbicide detection, offering a costeffective, portable and highly reliable platform for on-site environmental monitoring of pesticide residues.

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