Novel anti-oxidation electrochemical sensor based on rod-shaped polyaniline-carboxymethyl cellulose-copper nanoparticles for nitrite determination

In this paper, a new type of copper nanoparticles (Cu NPs) coated with antioxidant film was prepared, and a low-cost nitrite electrochemical sensor was constructed. Low-cost carboxymethylcellulose sodium (CMC-Na) and aniline were used as raw materials, and CMC-Na was used as the polymerization template of aniline to successfully prepare polyaniline-carboxymethyl cellulose nanorods (PANI-CMC). In order to slow down the oxidation rate of copper nanoparticles, CMC@copper nanoparticles (CMC@Cu NPs) containing 2.5 nm antioxidation film were prepared in consideration of the high water solubility, good chemical stability and strong film-forming ability of CMC. It turns out that the prepared PANI-CMC@Cu NPs/GCE had a good current response to nitrite with the linear detection ranges of 3-15,000 μM and 15,000-29,000 μM, and the limit of detection (LOD) of 0.170 μM (S/N= 3). The sensor based on the PANI-CMC@Cu NPs performed good stability and retained 91.3% of the initial sensitivity after 25 days. Meanwhile, the preparation cost of the sensor was extremely low owing to the  low price of raw materials in the experiment process, which made mass production possible.