氧化法制备荧光碳点及其应用

Synthesis of Fluorescent Carbon Dots by Oxidation and Its Application

以杉木为原料,经预炭化处理制成预炭化杉木粉,以之作为碳源,通过H_2O_2氧化法制得荧光碳点。采用透射电镜(TEM)、红外光谱(FT-IR)、X射线光电子能谱(XPS)和荧光光谱等分析手段对碳点微观形貌、光学特征等进行了表征,结果表明:碳点呈明显的球形,粒径为1~8 nm,表面含有羧基、羟基及氨基等基团,具有良好的水溶性和抗盐性能;碳点在335 nm激发光下发射出强蓝色荧光,最大发射波长455 nm,相对量子产率为8.3%,其荧光强度对pH值具有一定的敏感性。基于呋喃西林对碳点的荧光淬灭作用,采用不同浓度的呋喃西林对碳点荧光进行淬灭试验,研究发现:呋喃西林浓度在0.2~100μmol/L范围内,碳点荧光淬灭效率与呋喃西林浓度具有良好线性关系,线性方程为F_0/F=0.965+0.015c,线性相关系数为0.994 6,检出限为70 nmol/L。

Fluorescent carbon dots could be prepared by using pre-carbonized Chinese fir powder as the carbon source though the oxidation method. The obtained carbon dots were characterized by transmission electron microscopy（ TEM）,Fourier-transform infrared spectroscopy（ FT-IR）,X-ray photoelectron spectroscopy（ XPS） and fluorescence spectroscopy. The results showed that the carbon dots were spherical with the particle size of 1-8 nm,the surface of carbon dots had carboxyl,hydroxy and amino and so on,and the carbon dots had good water solubility and anti-salt property; the carbon dots emitted strong blue fluorescence with the maximum emission wavelength of 455 nm under the excitation band of 335 nm and the quantum yield was 8.3%. The intensity of the fluorescence was sensitive to the pH value. Based on the quenching effect of nitrofurazone on the fluorescence of carbon dots,the quenching experiment was conducted with different concentrations of nitrofurazone. As a result,a sensitive approach was developed for the detection of nitrofurazone in the range of 0.2-100 μmol/L with the detection limit of 70 nmol/L based on the fluorescence resonance energy transfer（ FRET） and inner filter effect（ IFE） between carbon dots and nitrofurazone with the linear equation of F_0/F = 0.965＋0.015 c and linear correlation coefficient of 0.994 6.