Carbon nanotube supported spherical NiFe-spinel heterostructure for sensitive electrochemical detection of aristolochic acid†

Aristolochic acid (AA) has strong carcinogenicity, and it has been reported that the medicinal and edible plant Houttuynia cordata may contain AA. Among transition metals, nickel and iron have outstanding catalytic ability for nitro reduction. The multivalent NiFe₂O₄ (NFO), which effectively promotes the redox reaction, has become a promising electrochemical material. In this work, we innovatively used a one-pot hydrothermal method to prepare NFO in situ on the surface of carbon nanotubes. For the first time, the composite NiFe₂O₄@MWCNTs (NFO@CNTs) was utilized to build a sensitive electrochemical sensor for detecting AA. The NFO@CNTs/GCE exhibited strong electrochemical performance due to the synergistic effect of high catalytic activity of NFO and good conductivity of carbon nanotubes. Furthermore, in order to provide a basis for the safe use of Houttuynia cordata, the electrochemical senor was successfully applied to detect AA in Chinese herbal medicines, confirming its practicability in real samples. This work broadens the application of nickel ferrite, which is expected to be a new candidate material for sensors.