4-Cyanophenol Herbicide Sensor Using Multi-Walled Carbon Nanotube Embedded Dual-Microporous Polypyrrole Nanoparticles As Metal-Free and Environmentally Friendly Hybrid Electrode

A highly sensitive 4-cyanophenol (4-CP) sensor was fabricated using multi-walled carbon nanotube (MWCNT)-embedded dual-microporous polypyrrole nanoparticle-modified screen-printed carbon electrodes (SPCE/DMPPy/MWCNT). The well-defined dual pores of DMPPy and MWCNT ( 0.53 and 0.65 nm) acted as good analyte absorption agents (shortening the ion diffusion path) and conducting agents (reducing the internal electron-transfer resistance). This enhanced electrical conductivity resulted in the improved electro-oxidation of 4-CP. A higher sensitivity (19.0 μA μM−1 cm−2) and lower limit of detection (0.8 nM) were achieved with a wide detection range of 0.001–400 µM (R2 = 0.9988). The proposed sensor exhibited excellent recovery of 4-CP in real-world samples. Therefore, the SPCE/DMPPy/MWCNT sensor is regarded highly suitable for rapidly detecting 4-CP.