Jayaweera Supuli, Yin Ke, Ng Wun Jern
Nanyang Environment & Water Research Institute and Interdisciplinary Graduate School, Nanyang Technological University, Singapore, Singapore.
Residues & Resource Reclamation Centre, Nanyang Environment & Water Research Institute, Nanyang Technological University, Singapore, Singapore.
J Fluoresc. 2019 Jan;29(1):221-229. doi: 10.1007/s10895-018-2331-3. Epub 2018 Dec 19.
Photoluminescent carbon dots have gained increasing attention in recent years due to their unique optical properties. Herein, a facile one-pot hydrothermal process is used to develop nitrogen-doped carbon dots (NCDs) with durian shell waste as the precursor and Tris base as the doping agent. The synthesized NCDs showed a quantum yield of 12.93% with a blue fluorescence under UV-light irradiation and maximum emission at 414 nm at an excitation wavelength of 340 nm. X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) spectroscopy showed the presence of nitrogen and oxygen functional groups on the NCD surface. The particles were quasi-spherical with an average particle diameter of 6.5 nm. The synthesized NCDs were resistant to photobleaching and stable under a wide range of pH but were negatively affected by increasing temperature. NCDs showed high selectivity to Tetracycline as the fluorescence of NCDs was quenched significantly by Tetracycline as a result of the inner filter effect. Based on sensitivity experiments, a linear relationship (R = 0.989) was developed over a concentration range of 0-30 μM with a detection limit of 75 nM (S/N = 3). The linear model was validated with two water samples (lake water and tap water) with relative recoveries of 98.6-108.5% and an RSD of <3.5%.
近年来，光致发光碳点因其独特的光学性质而受到越来越多的关注。在此，采用一种简便的一锅水热法，以榴莲壳废料为前驱体、三羟甲基氨基甲烷为掺杂剂来制备氮掺杂碳点（NCDs）。合成的NCDs在紫外光照射下呈现蓝色荧光，量子产率为12.93%，在340nm激发波长下的最大发射波长为414nm。X射线光电子能谱（XPS）和傅里叶变换红外（FTIR）光谱表明NCDs表面存在氮和氧官能团。这些颗粒呈准球形，平均粒径为6.5nm。合成的NCDs具有抗光漂白性能，在很宽的pH范围内稳定，但温度升高会对其产生负面影响。由于内滤效应，四环素可显著猝灭NCDs的荧光，因此NCDs对四环素具有高选择性。基于灵敏度实验，在0-30μM的浓度范围内建立了线性关系（R = 0.989），检测限为75 nM（S/N = 3）。用两个水样（湖水和自来水）对线性模型进行验证，相对回收率为98.6-108.5%，相对标准偏差<3.5%。
