A nonenzymatic electrochemical sensor for highly sensitive detection of thiophanate methyl based on MWCNTs functionalized bimetallic Fe/Cu MOF

Accurate detection of benzimidazole pesticide thiophanate-methyl (TM) is of vital importance due to its harm to environmental safety and human health. Herein, for the first time, we developed a sensitive nonenzymatic electrochemical sensor for TM detection based on multiwall carbon nanotubes (MWCNTs) functionalized bimetallic iron−copper organic frameworks (Fe/Cu MOF). The synthesized nanocomposites showed excellent electro-oxidation ability to TM owing to the synergistic effect between MWCNTs and Fe/Cu MOF. Fe/Cu MOF enhanced the specific surface area for MWCNTs and MWCNTs improved the conductivity for Fe/Cu MOF, which resulted in a nanocomposite with abundant catalytical active sites and superior conductivity, greatly amplifying the detection signal for TM. Under optimized conditions, the proposed sensor based on the composite presented a wide linearity from 0.3 nM to 200 nM which is wider than that of currently reported methods and a very low detection limit (LOD) of 0.1 nM far lower than the maximum residue levels (MRLs) enacted worldwide. Furthermore, the sensor showed good reproducibility, long-term stability and high anti-interference. Moreover, the sensor can be successfully employed for the determination of TM in apple and cucumber with good recoveries (80.96 %–105. 5 %), highlighting its excellent potential as an alternative to traditional techniques.