Nanosilver and protonated carbon nitride co-coated carbon cloth fibers based non-enzymatic electrochemical sensor for determination of carcinogenic nitrite

Yuliang Shen ^{a, 1}, Chuang Ma ^{a, 1}, Shupeng Zhang ^{a, d, e*}, Pengcheng Li ^{b, *}, Weiqing Zhu ^a, Xumei Zhang ^a, Juanjuan Gao ^a, Haiou Song ^{c, *}, Duozhe Chen ^a, Di Pang ^a, Aimin Li ^{d, e, *}

^‡ Y. Shen and C. Ma contributed equally to this work.

A novel electrochemical nitrite (NaNO₂) sensor was fabricated by combining nanosilver with protonated carbon nitride (H-C₃N₄) supported on carbon cloth (CC). H-C₃N₄ was distributed uniformly on the CC surface, providing more active sites for the electrocatalytic active center (nanosilver). CC as a substrate improved the H-C₃N₄ conductivity and provided the sensor with a flexible feature. The strong synergistic effect between CC, H-C₃N₄, and nanosilver can exert a significant electrocatalytic performance on the flexible sensor. The Ag/H-C₃N₄/CC flexible sensor electrode did not consume much more time to polish the surface of traditional electrodes, and possessed a high sensitivity of 0.85537 μA/mg, a wide linear response range that spanned 5 to 1000 μM, a low detection limit of 0.216 μM (S/N = 3), and high selectivity for nitrite in the presence of common organic and inorganic interfering species (such as CaCl₂, NaCl, MgCl₂, NaNO₃, glucose, urea, and p-nitrophenol). The Ag/H-C₃N₄/CC flexible sensor can be used for sample detection of nitrite as it has a strong anti-interference ability, good reproducibility, repeatability, and long-term stability. The Ag/H-C₃N₄/CC sensor is a promising alternative electrode to traditional ones such as ITO, gold or glassy carbon electrodes.