Electrochemical sensing platform based on graphitized and carboxylated multi-walled carbon nanotubes decorated with cerium oxide nanoparticles for sensitive detection of methyl parathion

Abstract

We proposed a low-cost ultrasonic-assisted strategy to prepare the graphitized and carboxylated carbon nanotubes (GR-MWCNTs-COOH) and cerium oxide (CeO2) nanoparticles nanocomposite, which was applied to fabricate the GR-MWCNTs-COOH@CeO2/GCE sensor for the electrochemical detection of methyl parathion (MP). GR-MWCNTs-COOH with graphitization and carboxylation showed excellent conductivity property, large surface area, and gratifying hydrophilicity. Graphitization enhanced the electrical conductivity of MWCNTs, and carboxylation promoted the homogeneous dispersion of MWCNTs. The double-functionalization of MWCNTs helped form the interconnected carbon nanotubes conductive network. CeO2 nanoparticles with good catalytic ability possessed high enrichment capability of MP because of the good affinity between CeO2 and phosphate groups. Moreover, the double-functionalized GR-MWCNTs-COOH not only promoted the uniform dispersion of CeO2 nanoparticles but also compensated for the poor electrical conductivity of CeO2 nanoparticles. The GR-MWCNTs-COOH@CeO2/GCE sensor presented a low detection of limit of 0.0285 μM (MP concentration range: 0.01–10 μM). The satisfactory reproducibility, repeatability, and anti-interference were obtained at the fabricated nanohybrid sensor. When applied for the MP determination in spinach and cabbage samples, the low RSD values of 1.71–4.25% and satisfactory recoveries of 95.8–100.7% could be achieved at the GR-MWCNTs-COOH@CeO2/GCE sensor. This work provided an important reference for the design of high-performance MP sensor.