Red-emissive carbon dots from Hibiscus rosa-sinensis: a detailed appraisal of tartrazine dye sensing properties.

An economically viable and greener approach is introduced to fabricate red emissive carbon dots (R@CQDs) via employing hydrothermal means on Hibiscus rosa-sinensis leaves as precursor source. The obtained R@CQDs displayed excitation-dependent behavior, with high aqueous stability, quantum yield of 56%, and outstanding fluorescence aptitude under the conditions of varied range of ionic strength and pH (1-12). The fluorescence emission behavior of R@CQDs displayed selective turn off fluorescence response to tartrazine over other interfering species with a limit of detection of 0.09 µM and quantitation limit of 0.30 µM. Theoretical calculations employing density functional theory (DFT) were carried out to complement experimental findings and getting insights into the underlying mechanism governing the sensing of tartrazine. The developed sensor holds significant potential for tartrazine detection in real samples and offering wider prospective in the food safety assessment.