Fabrication of Methyl Parathion Electrochemical Sensor Based on Modified Glassy Carbon Electrode with Graphitized and Carboxylated Multi-Walled Carbon Nanotubes Decorated with Zirconia Nanoparticles

Herein, we modified the glassy carbon electrode (GCE) by using the nanocomposite of graphitized and carboxylated multi-walled carbon nanotubes (GR-MWCNTs-COOH) and zirconia (ZrO 2 ) nanoparticles for the fabrication of GR-MWCNTs-COOH/ZrO 2 /GCE sensor. GR-MWCNTs-COOH had high electrical conductivity, large specific surface area, and good hydrophilicity. ZrO 2 nanoparticles possessed strong affinity toward the phosphorus groups on methyl parathion (MP) molecules, which contributes to the enrichment of MP on the modified GCE surface. The fabricated GR-MWCNTs-COOH/ZrO 2 /GCE sensor exhibited excellent electrochemical sensing performance for the determination of MP due to the synergistic effect of GR-MWCNTs-COOH and ZrO 2 . Under the optimal conditions, the GR-MWCNTs-COOH/ZrO 2 /GCE sensor could show a low limit of detection of 0.00135 μM in linear MP concentration range of 0.01-10 μM. Moreover, the fabricated sensor presented good reproducibility, repeatability, and selectivity, which could promote the practical application of MP sensor.