A naphthalimide-based fluorescent probe for rapid detection of nitrite and its application in food quality monitoring

Abstract

Nitrite (NO2−) is a widely used food additive and long-term aging of cooked leftovers may also contribute to the formation of NO2−, excessive consumption of NO2− is harmful to human health. Developing an effective sensing strategy for on-site monitoring of NO2− has attracted considerable attention. Herein, a novel colorimetric and fluorometric probe ND-1 based on photoinduced electron transfer effect (PET) was designed for highly selective and sensitive detection of nitrite (NO2−) in foods. The probe ND-1 was strategically constructed by employing naphthalimide as the fluorophore and o-phenylendiamine as the specific recognition site for NO2−. The triazole derivative ND-1-NO2- could be produced exclusively by reacting with NO2−, leading to a visible colorimetric change from yellow to colorless accompanied by a significantly enhanced fluorescence intensity at 440 nm. The probe ND-1 exhibited promising sensing performances towards NO2− including high selectivity, rapid response time (within 7 min), low detection limit (47.15 nM) and wide quantitative detection range (0–35 μM). In addition, probe ND-1 was capable of quantitative detecting of NO2− in real food samples (including pickled vegetables and cured meat products) with satisfactory recovery rates (97.61%–103.08%). Moreover, the paper device loaded by probe ND-1 could be utilized for visual monitoring of NO2− levels variation of stir-fried greens. This study provided a feasible method for the accurate, traceable and rapid on-site monitoring NO2− in foods.