Facile fabrication of Zr-based metal–organic framework/Ketjen black-carbon nanotubes composite sensor for highly sensitive detection of methyl parathion

A novel methyl parathion (MP) electrochemical sensor was fabricated from the multifunctional composite of Zr-based metal–organic framework (UiO-66) and Ketjen black-carbon nanotubes (KB-CNTs), which achieved the sensitive detection of MP in food samples. For the UiO-66/KB-CNTs composite, Zr-based UiO-66 with Zr-OH groups possessed good affinity for phosphate groups on methyl parathion molecules, which enhanced the selective recognition and enrichment capability towards MP, and KB-CNTs possessed three-dimensional interconnected carbon conductive network with synergistic point-line carbon conductive contact, which showed excellent electrical conductivity. Moreover, KB with pearl chain-like structure and more conductive contact points realized the full contact between KB-CNTs and UiO-66 with Zr-OH groups. The fabricated UiO-66/KB-CNTs/GCE sensor showed good MP detection performance with low limit of detection of 1.53 nM in linear MP concentration range of 0.005–12 µM. Moreover, the fabricated sensor showed good repeatability, reproducibility, and selectivity. A good practical feasibility can be achieved at the UiO-66/KB-CNTs/GCE sensor for the detection of MP in grape juice and apple juice samples (Recovery rate: 96.14–102.93, relative standard deviation: 2.17%-4.95%).