Green One step Synthesis of Carbon dots from Grapes peel, Characterization and Application as a Fluorescence Probe for the Detection of some Heavy, Light Metals ions and DNA Binding

Recent advancements in analytical techniques for detecting crucial chemicals and biological substances, including metal ions, have highlighted the limitations of traditional methods such as potentiometric sensors, electrochemical sensors, and spectrometry techniques, which are often costly, time-consuming, and unsuitable for real-time monitoring. Fluorescence assay methods offer high sensitivity, selectivity, and rapid analysis with simpler sample preparation. This study presents an eco-friendly, rapid, and cost-effective method for synthesizing biocompatible fluorescent carbon dots (CDs) from grapefruit peels via a one-step solvothermal process. The synthesized CDs exhibit stable photoluminescence, excellent biocompatibility, and low toxicity, making them suitable for metal ion detection and DNA sensing. Characterization using fluorescence spectrophotometry, UV-Vis spectrophotometry, FTIR spectroscopy, and TEM confirmed the CDs’ spherical morphology, optical properties, and various functional groups. The CDs demonstrated high sensitivity for detecting metal ions, with fluorescence quenching observed in the presence of Cu²⁺ (R² = 0.9998) and Al³⁺ (R² = 0.9898), and detection limits of 0.5 ppm. Stability tests showed minimal impact on fluorescence intensity with varying KCl concentration, pH, long term storage and temperature. Additionally, the CDs exhibited significant fluorescence quenching in the presence of DNA, indicating their potential for biological sensing with a detection limit of 0.4 ppm. This study underscores the potential of CDs for sensitive and selective environmental monitoring and biological applications, offering a sustainable approach to managing agricultural waste.