Microwave abetted synthesis of carbon dots and its triple mode applications in tartrazine detection, manganese ion sensing and fluorescent ink

Carbon dots (CDs) are the emerging class of carbon-based nanomaterials with immense applications in various fields. In this work, CDs were synthesized using a simple microwave method using citric acid and tris base as precursors. The highly photoluminescent CDs were well characterized for examining the structural and optical properties. It was found successful for triple mode applications in food, metal ion sensing and fluorescent ink. As an inner filter-based fluorescent sensor, CDs detected tartrazine with an LOD (limit of detection) of 54 nM in the linear range 2–12 μM. The practicability of the probe was confirmed using its analysis in food samples. It also worked well as an electrochemical sensor for detecting Mn(II) ions in real water samples with a very low LOD of 0.37 nM. Finally, CDs were employed as a fluorescent ink for drawing and writing applications. High fluorescence of the as prepared CDs thus proved its potential for anticounterfeiting applications. This work not only adds new knowledge and data on material properties through thorough characterization of a new CD but also introduces a new sensor that is capable of triple mode application with excellent selectivity, sensitivity and practical viability.