RESUMEN
Catechol, which has a high toxicity and low degradability, poses significant risks to both human health and the environment. Tracking of catechol residues is essential to protect human health and to assess the safety of the environment. We constructed sensing platforms to detect catechol based on the conductive metal-organic frameworks [Ni3(HITP)2] and their nanosilver composites. The reduction process of catechol at the Ni3(HITP)2/AgNP electrode is chemically irreversible as a result of the difference in compatibility of the oxidation stability and conductivity between the Ni3(HITP)2/AgNS and Ni3(HITP)2/AgNP electrodes. The electrochemical results show that the Ni3(HITP)2/AgNS electrode presents a lower detection limit of 0.053 µM and better sensitivity, reproducibility and repeatability than the Ni3(HITP)2/AgNP electrode. The kinetic mechanism of the catechol electrooxidation at the surface of the electrode is controlled by diffusion through a 2H+/2e- process. The transfer coefficient is the key factor used to illustrate this process. During the electrochemical conversion of phenol to ketone, more than half of ΔG is used to change the activation energy. We also studied the stability, anti-interference and reproducibility of these electrode systems.
RESUMEN
An electrochemical sensor composed of conductive metal-organic framework [Ni3(HITP)2] and molecular imprinted polymers (MIP) is fabricated to detect dopamine. Ni3(HITP)2 promotes electrons transfer due to the structure of in-plane charge delocalization and layered expansion conjugation. The combination of MIP with Ni3(HITP)2 improves the selectivity and conductivity, exhibiting a wide detection range (0.06 ~ 200 µM) and a low detection limit (0.109 µM). The kinetic mechanism on the electrode surface is an adsorption controlled process, with the equal number of electrons and protons participating in oxidation in the electrocatalytic process of catechol converting to o-quinone.