High Sensitivity Detection of Nitrite Electrochemical Sensor Modified with MOF Composite Materials

Depositing composites of Ni-HHTP and MWCNTs on a glassy carbon electrode(GCE) have developed a sensitive and facile electrochemical sensor for nitrite detection. Ni-HHTP@MWCNTs composites were synthesized in situ using 2,3,6,7,10,11-hexahydroxytriphenylene (HHTP), nickel acetate tetrahydrate Ni(OAc)₂·4H₂O and multi-walled carbon nanotubes (MWCNTs) by hydrothermal method. The composite electrode was prepared by the coating method. The synergistic combination of Ni-HHTP and MWCNTs enables the electrode to possess fast electronic conductivity and generate sensitive electrochemical signals for sodium nitrite (NaNO₂). The controlled variable approach determines the best test conditions for the analyte and obtains a susceptible response signal. The composite electrode has an extensive linear response range of 1-10000 μM to NaNO₂, with a detection limit of 0.95 μM and sensitivity of 0.96 mA·mM⁻¹·cm⁻², which shows excellent reproducibility and stability performance. There are no interferences from the most common ions. The electrochemical analysis method was used for nitrite detection in actual water samples with a recovery rate of 97.2%-103.7%, indicating this composite material’s practical application potential. The mechanism of the specific electrochemical process on the modified electrode was also explored. This work preliminarily explored new electrochemical sensors for high-precision nitrite detection and precise sensing in analysis tests.