Development of a ratiometric fluorescence sensor based on blue- and orange-emissive carbon dots for the determination of tartrazine in food products

Determination of tartrazine in food products is crucial due to its detrimental impacts on human health if it exceeds the maximum allowed intake limit. It was hypothesized that a ratiometric fluorescence sensor using blue- and orange-emissive carbon dots (B-O-CDs) would outperform single-emission-based sensors in sensitivity and reproducibility. A ratiometric probe was developed by mixing B-CDs and O-CDs, exhibiting emission peaks at 420 and 565 nm, differentially influenced by tartrazine. The fluorescence intensity ratio was used to quantify tartrazine with a detection limit of 64 nM, a linear range of 0.2–60 μM, recovery rates of 97.2–104.4 % and low relative standard deviation values (< 3.5 %) in food samples. The results confirm that the ratiometric approach enhances performance over single-emission-based sensors. The novel use of dual-emissive carbon dots and the inner filter effect offers a rapid, cost-effective, and reliable method for routine tartrazine monitoring in food products.