Optimized Microwave-Assisted Synthesis Of Dithizone-Doped Chitosan Carbon Dots For Enhanced Photoluminescence And Lead(Ii) Ion Detection
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Kiryigitova Sevara Botirovna
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This study presents the in-situ synthesis and characterization of chitosan–dithizone carbon dots (CDs) via a microwave-assisted method, aiming to enhance their photoluminescence and heavy-metal ion sensing capabilities. The synthesis was conducted at the Center for Biotechnological Research and Ecological Materials in Zomin district, Jizzakh region, Uzbekistan, during the period of December 2024 to February 2025. Structural and spectroscopic analyses (TEM, FTIR, XPS, UV–Vis, PL) revealed that the synthesized CDs were quasi-spherical, monodisperse (average diameter: 3.7 ± 0.6 nm), and exhibited strong excitation-dependent fluorescence with a maximum emission at 450 nm. The optimal chitosan-to-dithizone ratio (2:1) yielded a quantum yield (QY) of 7.12 %. The presence of thiocarbonyl and amine groups on the CD surface significantly improved selectivity toward Pb²⁺ ions, achieving a detection limit of 18.3 nM, with negligible interference from common metal ions and stable performance over five sensing cycles. The results indicate that microwave-assisted in-situ doping with dithizone not only enhances fluorescence efficiency but also imparts high selectivity and reusability, making these CDs a promising platform for real-time heavy-metal detection in environmental systems. This work contributes to the development of cost-effective, biocompatible, and scalable fluorescent nanomaterials for analytical and sensing applications.
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Kiryigitova Sevara Botirovna
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References:
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