Optical Sensing Techniques for Nitrite Detection: A Comprehensive Review and Future Perspectives

Nitrite (NO₂ ^-), a critical inorganic nitrogenous compound, has extensive applications in the food industry. However, its excessive intake poses significant health and ecological risks. Therefore, the accurate quantitative detection of NO₂ ^- is of great importance for both scientific research and practical applications. In recent years, optical sensing technology has emerged as a key tool for NO₂ ^- detection in food samples, due to its high sensitivity, rapid response, and user-friendly operation. This paper provides a systematic review of the detection principles underlying typical optical sensing techniques, including ultraviolet-visible absorption spectroscopy/colorimetry, fluorescence spectroscopy, surface-enhanced Raman spectroscopy, and chemiluminescence/electrochemiluminescence. It highlights recent advancements in NO₂ ^- analysis using these techniques, both individually and in multimodal. Despite their many advantages, current optical sensing techniques for NO₂ ^- face several practical challenges, such as limited anti-interference capabilities, difficulties in synergistically optimizing sensitivity and selectivity, and issues with real-sample applicability. This paper explores potential solutions to these challenges in-depth and outlines the primary directions for future research. Optical sensing technology has made important breakthroughs in the field of nitrite detection, exhibiting considerable potential for application. In view of the existing technical problems and practical application challenges, it is urgent to deepen the research, so as to provide more reliable technical support for food quality monitoring.