Gold nanoparticles and carboxylated carbon nanotubes co-functionalized black phosphorene for ultrasensitive electrochemical detection of benomyl residues

Benomyl (BEN) was widely employed in agriculture as an efficient broad-spectrum benzimidazole fungicide. However, overuse of BEN aroused extensive human health concerns. Electrochemical sensors are promising techniques for residue analysis but are seriously limited by insufficient sensitivity and electrode contamination in BEN detection. Herein, an electrochemical sensor based on Au nanoparticles and MWCNTs-COOH co-modified black phosphorus (BP) was developed for BEN detection. This unique heterostructure of BP-Au/MWCNTs-COOH significantly enhanced the electrochemically active surface area (EASA), charge transfer efficiency, and antifouling effect. The fabricated BP-Au/MWCNTs-COOH/GCE electrochemical sensor demonstrated good analytical performances with a wide linear range (0.007–1.0 μM), ultralow detection limit (1.54 nM), high repeatability, good selectivity and long-term stability. In addition, the sensor achieved high recoveries of 97.36–114.3 % in real food samples, highlighting its potential for rapid and trace-level monitoring of BEN in agricultural products.