Ag Nanoparticles Functionalized Graphitic Carbon Nitride Nanosheets for Dual Detection of Tartrazine and Sunset Yellow in Food Samples

The widespread use of azo dyes in food raises serious health concerns, necessitating a sensitive and reliable detection method. In the present research work, graphitic carbon nitride (gCN) sheets were fabricated and functionalized with silver (Ag) nanoparticles. The Ag/gCN nanocomposite showed intense blue fluorescence at 440 nm upon excitation at 370 nm, enabling the detection of tartrazine (Tz) and sunset yellow (SY) with limits of detection (LODs) of 0.634 and 0.464 μM, respectively. A fluorescent film was developed for rapid, on-site visual detection. The fluorescence quenching occurred via inner filter effect (IFE) and static mechanisms. The practicality of the sensor was tested on soft drinks, turmeric powder, and candies, yielding average recoveries in the range of 95.70–101.42% showing its high accuracy and reliability. The results highlight the potential of the Ag/gCN nanocomposite as a cost-effective and efficient fluorometric sensor for food colorants in real-world applications.