Fabrication of nano-copper/carbon nanotubes/chitosan film by one-step electrodeposition and its sensitive determination of nitrite

In this paper, Cu nanoparticles/carbon nanotube/chitosan (Cunano/CNTs/CS) film was one-step electrodeposited onto the glassy carbon electrode (GCE), which fabricated a Cunano/CNTs/CS/GCE sensor to detect nitrite. One-step electrodeposition of CNTs and Cunano with the chitosan (CS) hydrogel was achieved, and the whole procedure takes only several minutes. Scanning electron microscopy (SEM) image demonstrated that the Cu nanoparticles coated on CNTs/CS were uniform, with an average size of 30 nm. The effects of Cu2+, CNTs and CS concentration in the mixture together with electrodeposition time and determination conditions such as applied potential, pH value on the current response of Cunano/CNTs/CS/GCE toward nitrite were optimized to obtain the maximal sensitivity. In addition, electrochemical experiments revealed that the modified electrode showed high electrocatalytic activity to the reduction of nitrite ion (NO2−). The linear range for the detection of NO2− was 1.0 × 10−7 M to 2.5 × 10−3 M with a high sensitivity of −48.92 μA mM−1, and the response was very fast (less than 2 s). A low detection limit of 2.4 × 10−8 M (S/N = 3) for NO2− was achieved.