Carbon nanodots derived from glycine for rapid detection of caffeine in beverages

Caffeine, a widely consumed stimulant, requires precise monitoring in food and beverages to ensure consumer safety. However, conventional detection methods, such as high-performance liquid chromatography (HPLC), are time-consuming, costly, and equipment-intensive. To overcome these limitations, we present a novel fluorescent sensing platform based on glycine-derived carbon nanodots (Gly-CNDs) for rapid and cost-effective caffeine detection. Unlike existing sensors, our food-grade Gly-CNDs offer enhanced biocompatibility, stability, and selectivity while eliminating the need for complex synthesis or toxic reagents. The synthesized Gly-CNDs, with an average size of 4.2 ± 1.2 nm, exhibited a significant fluorescence enhancement upon caffeine binding, enabling highly sensitive detection within 39–2060 nM range with a low limit of detection (LOD) of 36.5 nM. Tested with beverage samples, this green method offers a promising alternative for monitoring caffeine in foods and could be applied to detect other contaminants and bioactive compounds. • A fast and cost-effective technique for measuring caffeine in food and drinks. • Carbon nanodots are derived from food-grade materials (glycine and sugars) to ensure food safety. • Glycine-carbon nanodots, averaging 4.2 ± 1.2 nm, were stabilized under different conditions. • The caffeine content closely aligns with the results obtained from the HPLC method. • The optimal experimental conditions are an acidic pH.