Debnath Joy, Hosseini-Bandegharaei Ahmad, Ghosh Kalyan Sundar
Department of Chemistry, National Institute of Technology Hamirpur, Hamirpur, Himachal Pradesh, India.
Department of Chemistry, School of Chemical and Biotechnology, SASTRA Deemed to Be University, Thanjavur, Tamil Nadu, India.
Luminescence. 2025 Jul;40(7):e70260. doi: 10.1002/bio.70260.
Carboneous nanomaterials derived from natural sources are being used as chemosensors due to their small size, water solubility, photostability, tunable emission properties, etc. In the present work, highly fluorescent and photostable carbon dots (CDs) having an average size of 11 nm were prepared from Citrus reticulata through a one-step hydrothermal process. CDs emitted a strong green fluorescence under UV light. The prepared CDs were characterized using TEM, XRD, XPS, FTIR, UV-Vis, and fluorescence techniques. Maximum emission intensity of CDs was recorded at 438 nm on excitation at 350 nm. The quantum yield of CDs was 4.4%. CDs selectively detected Fe ions colorimetrically through a visual change in color from colorless to yellow. Also, among other metal ions, only Fe selectively quenched the emission of CDs. Fluorescence quenching by Fe was static in nature and due to the formation of a ground state complex between the metal ion and the surface functionalities on CDs. From the spectroscopic data, it was concluded that CDs can detect Fe within the linear range of 6.2-620 μM, and the limit of detection was 1.11 μM. Based on rapid, label-free, and selective detection capabilities, CDs were further used in the analysis of Fe in real water samples.
源自天然来源的碳质纳米材料因其尺寸小、水溶性、光稳定性、可调节发射特性等而被用作化学传感器。在本工作中，通过一步水热法从柑橘中制备了平均尺寸为11纳米的高荧光且光稳定的碳点（CDs）。碳点在紫外光下发出强烈的绿色荧光。使用透射电子显微镜（TEM）、X射线衍射（XRD）、X射线光电子能谱（XPS）、傅里叶变换红外光谱（FTIR）、紫外可见光谱（UV-Vis）和荧光技术对制备的碳点进行了表征。在350纳米激发下，碳点的最大发射强度在438纳米处记录。碳点的量子产率为4.4%。碳点通过从无色到黄色的颜色视觉变化比色法选择性检测铁离子。此外，在其他金属离子中，只有铁选择性地猝灭了碳点的发射。铁引起的荧光猝灭本质上是静态的，并且是由于金属离子与碳点表面官能团之间形成了基态络合物。从光谱数据得出结论，碳点可以在6.2 - 620微摩尔的线性范围内检测铁，检测限为1.11微摩尔。基于快速、无标记和选择性检测能力，碳点进一步用于实际水样中铁的分析。
