Non-precious metal-modified sensors for nitrite detection

Nitrite is widely used due to its personal properties. It not only exists in the food processing and chemical industry but also in every corner of the natural world. Nevertheless, excessive use of nitrite can cause serious environmental and human health hazards. Therefore, the efficient and sensitive detection of nitrite content has become a problem that must be faced. Among numerous methods, the electrochemical method has been widely studied for its advantages, such as fast reaction speed, high sensitivity, and miniaturization. The principle of operation of the nitrite electrochemical sensor is as follows. A modified layer located on the electrode surface oxidizes nitrite to nitrate. The sensing signal generated during oxidation can be converted into a measurable electrochemical signal. The electrochemical signal is proportional to nitrite concentration within a certain range, so that nitrite can be quantitatively detected. However, the sensor's performance is affected by the high oxidation potential of the bare electrode in electrochemistry. Therefore, the electrode is often modified to improve the sensor's performance in the study. In this review, the research progress of materials other than precious metals is discussed in the electrochemical detection of nitrite in recent years (2023-2013). The properties of carbon materials, non-noble metals, metal-organic framework compounds, conductive polymers, and their composites in electrochemical sensors are discussed in detail. Besides, it also looks forward to the challenges and prospects of nanomaterials in electrochemical sensor applications.Graphical AbstractArticle overall summary diagram