Highly Sensitive Portable Test Strip Based on Carboxylate Cellulose‐Derived Carbon Dots for On‐Site Visual Detection of Nitrite in Food Samples

Abstract As a common food additive, nitrites are used in processed meat products, primarily for color enhancement and preservation. Excessive intake of nitrites can lead to high toxicity to pose a significant risk to human health, including potential carcinogenicity and even death. Consequently, developing a rapid and sensitive method for nitrite detection is crucial for food safety monitoring. Herein, this study is developing a nitrite detection system utilizing blue‐fluorescent carbon dots (CDs) derived from carboxylate cellulose. This system operates by detecting the quenching of CDs fluorescence, which is caused by Fe³⁺ ions generated via the oxidation of Fe²⁺ by nitrite under acidic conditions. Within a concentration range of 1–1000 µm, the system demonstrates a strong linear relationship between CDs fluorescence intensity and nitrite concentration, with a detection limit of 0.42 µm. Furthermore, this study is designing a novel CDs‐based fluorescent test strip for rapid and visual nitrite quantification in pakchoi cabbage samples, enabling detection within 30 min. Overall, the CDs‐based fluorescent test strips hold great promise for enhancing food safety monitoring, ensuring effective nitrite control, and protecting public health from the potential risks associated with excessive nitrite consumption.