Electrochemical sensor for sensitive determination of nitrite based on the CuS–MWCNT nanocomposites

• CuS–MWCNT nanocomposites were synthesized by employing MWCNTs as the catalyst support.
• It was the first demonstration of fabricating the nitrite sensor based on CuS–MWCNT nanocomposites.
• This sensor exhibits remarkable catalytic performance for nitrite detection.

A functional nanocomposite of copper sulfide nanoparticles (CuS) supported on multiwall carbon nanotubes (MWCNTs) was synthesized and used for fabricating a nitrite sensor. X-ray diffraction analysis indicated that the product was CuS–MWCNTs. The morphology of the nanocomposite was studied by transmission electron microscopy. The glass carbon electrode modified with CuS–MWCNTs showed excellent electrocatalytic activities to the oxidation of nitrite in pH 7.0 phosphate buffer. The sensor could detect nitrite in a linear range of 1.0 μM to 8.1 mM with a correlation coefficient of 0.9989 and sensitivity of 131.2 μA mM− 1 cm− 2, a detection limit of 0.33 μM at a signal-to-noise ratio of 3. Additionally, the sensor exhibited good reproducibility, long-term stability, and anti-interference.