Electrochemical determination of nitrite via covalent immobilization of a single-walled carbon nanotubes and single stranded deoxyribonucleic acid nanocomposite on a glassy carbon electrode

A novel method has been developed for determination of nitrite by modifying the surface of a glassy carbon electrode (GCE) using single-walled carbon nanotubes with covalently immobilized single-strand deoxyribonucleic acid. The modified electrodes were characterized by field emission scanning electron microscopy, X-ray photoelectron spectroscopy, and electrochemical techniques. The results demonstrate that the nanotube-DNA nanocomposite has been successfully immobilized on the surface of the GCE. The new electrode, under optimum conditions at room temperature, exhibits excellent electrocatalytic activity towards the oxidation of nitrite, with a significantly reduction of the overpotential. The linear range for the detection of nitrite is from 0.6 to 540 μM, with a sensitivity of 0.216 μA μM⁻¹, and a detection limit as low as 0.15 μM. The electrode showed good reproducibility and high stability and was successfully used to analyze nitrite in water and sausage samples.