engleski

Preparation and Characterization of N-Doped/Hybrid Carbon Quantum Dots and Their Application in Metal Ion Detection

Carbon quantum dots (CQDs) represent a new class of efficient carbon photoluminescent nanomaterials that have attracted the attention of many scientists over the past decade, especially due to their excellent chemical and optical properties. In general, carbon dots are defined as zero- dimensional carbon-based nanoparticles with a diameter less than 20 nm, while the specific applicability mostly depend on the nanoparticle size, shape, composition, and surface features. Their high chemical and photo-stability, biocompatibility/low toxicity, tunable emission, water solubility and optical efficiency represent a huge potential for a wide range of applications in biomedical research and nanotechnology. This work presents a comparative study of the CQDs preparation from Citrus clementina peel and citric acid. In order to obtain best performing hybrid nanoparticles (CQD@hybrid), pre-optimization regarding synthetic conditions, type and quantity of added amino acids has been performed. The main aim of this study was to enhance quantum yield (QY) of prepared samples, also to improve their bioactivity, and to achieve selective response toward Fe3+ ions. The highest quantum yield was determined with CQD@hybrid obtained with the addition of amino acid leucine (Leu), treated at temperature of 200°C for 12 hours, and this sample was further investigated for the Fe3+ ion sensing. The developed model was described by an exponential function with a suitable coefficient of determination of R2 = 0.9851, while the linear range was determined in the concentration range from 0.5 μmol dm-3 to 15 μmol dm-3 with a determined limit of detection of LOD = 2.72 ± 0.39 μmol dm-3 and limit of quantification of LOQ = 9.06 ± 1.29 μmol dm-3. The developed model has been tested for the Fe3+ ions detection in real sample systems of well water samples. These presented results are indicative of a good preparative approach toward obtaining highly fluorescent CQDs, showing also good stability in aqueous media with significant differences in optical properties, while showing great potential for the studies in biological systems and water monitoring.

carbon quantum dots ; nanoparticle functionalization ; metal ion detection ; bioactivity

nije evidentirano