Gamma Irradiation Synthesis of Sugar-Derived Carbon-Dot-Functionalized Glutathione for Hg²⁺ Detection and Antioxidant Activity

Mercury, a particularly toxic heavy metal from industrial processes, poses significant risks to both people and the environment when it accumulates to dangerous levels, damaging the liver, kidneys, and nervous system. Therefore, fluorescent organic carbon dots (CDs) were developed for detecting Hg²⁺ ions. These CDs were easily synthesized, chemically stable, biocompatible, low in toxicity, and environmentally friendly. In this work, glutathione-functionalized CDs (CDs-GSH) were produced from sugar using the EDC/NHS coupling method. Gamma irradiation induced the chemical reactions necessary to produce fluorescent CDs. CDs-GSH demonstrated significant selectivity for Hg²⁺ with an 83% reduction in fluorescence intensity. Additionally, they exhibited a phenolic content of 19.1 μg/mg GAE and strong antioxidant characteristics, with DPPH radical scavenging activity of 63% at 1.0 mg/mL. Due to their stability, selectivity, and antioxidant qualities, high-value CDs can be produced from table sugar using an environmentally friendly synthesis process, offering potential applications in sensing and antioxidant activity.