Electrochemical detection of nitrite in medical and environmental samples with oxidation modified carbon fiber electrode

The potential toxicity of nitrite to organisms and the environment makes it necessary to build a sensitive and accurate nitrite detection platform. The oxidation-modified carbon fiber electrode (OMCF) with a rougher surface and oxygen-containing functional groups is constructed by a simple high-temperature calcined treatment at 400 °C for 2 h for sensitive detection of nitrite. The amperometric test results exhibit that OMCF has two linear ranges of 1–1000 µM and 1000–6000 µM. Besides, its corresponding sensitivities are 988.57 and 668.51 µA mM−1 cm−2, respectively. The low detection limit is 0.1 µM. Importantly, the OMCF can be used to detect nitrite in a drop of water or medical samples. In addition, the OMCF with a length of 150 cm was successfully synthesized. The nine sections of the above OMCF are randomly selected to detect nitrite, which shows good reproducibility. Therefore, this work provides a facile method for preparing OMCFs with high sensitivity and wide linear range for the electrochemical detection of nitrite in urine and enables large-scale electrode production for medical applications.