Exploring Biomass-Derived Carbon Dots as Multifunctional Fluorescent Material for Metal Ion Sensing and Anticounterfeiting.

Lead contamination in the environment severely threatens human health due to its high toxicity, particularly in water sources. Exposure to lead ions (Pb²⁺) can cause neurological disorders, kidney damage, and developmental impairments, necessitating the development of sensitive and selective detection methods. Biomass-derived fluorophores, such as carbon dots (CDs), have emerged as eco-friendly and cost-effective alternative sensors that offer high sensitivity while overcoming the limitations of conventional techniques. This work reports a fluorescence-quenching sensor for lead ion (Pb²⁺) based on CDs synthesized from biomass (Saccharum spontaneum). The CDs are synthesized via a hydrothermal process. Optical studies reveal a fluorescence quenching of CDs in the presence of Pb²⁺ ions due to the complex formation of CDs through functional groups, enabling highly sensitive lead detection. The CDs exhibit a low detection limit of 376 nM, demonstrating its potential as a reliable lead sensor. These CDs are further explored as fluorescent ink for anticounterfeiting applications.