A Metal-Organic Gel-Carbon Nanotube Nanocomposite for Electrochemical Detection of Nitrite

A nanocomposite material consisting of a copper ion-based metal-organic gel (MOG-Cu) and multiwalled carbon nanotubes (MWCNTs) was prepared and served to construct a sensor for electrochemical detection of nitrite. The micromorphology of the MOG-Cu-MWCNT nanocomposite was characterized. The effects of MWCNT doping on the formation of a Cu-based MOG and its electrochemical property for nitrite electro-oxidation were evaluated. It shows that the optimal amount of MWCNTs does not influence the formation and nanofiber structure of the Cu-based MOG but can increase the electrochemical surface area and facilitate the interfacial charge transport. Hence, the oxidation current of nitrite at the MOG-Cu-MWCNT-coated glass carbon electrode (GCE) is considerably enhanced in contrast to the MOG-Cu/GCE. The analytical performances of the MOG-Cu-MWCNTs/GCE for electrochemical detection of nitrite were investigated. Operated in optimum conditions, the oxidation peak current at a potential of about 0.77 V versus a saturated calomel electrode shows direct proportion correlation with concentration of nitrite. The linear range is 0.3-100 mu M. The sensor demonstrates fair anti-interference capacity, high sensitivity, a low detection limit (0.086 mu M), satisfactory reproducibility, and storage stability, being a valuable tool for the electrochemical monitoring of nitrite in food samples.

Automated summary

A nanocomposite material consisting of MOG-Cu and MWCNTs was prepared and used as a sensor for electrochemical detection of nitrite. The addition of MWCNTs did not affect the formation and structure of the composite material, but increased the electrochemical surface area and facilitated charge transport, leading to enhanced oxidation current of nitrite. The sensor demonstrated high sensitivity, low detection limit, and good reproducibility, making it a valuable tool for monitoring nitrite in food samples.