壳聚糖基碳量子点的制备、表征及其对过氧化氢的荧光检测研究

为制备可用于分析过氧化氢(H₂O₂)的荧光传感器,本研究利用壳聚糖与DL-酒石酸为反应前体,水热处理制备了新型氮掺碳量子点(CDs),能够高效、简便地检测食品中的H₂O₂含量;并采用透射电镜(TEM),以及傅里叶变换红外光谱(FTIR)等方法进行分析表征。结果表明,CDs的荧光量子产率约为5.22%,粒径约为20 nm,而且具有石墨烯结构,其表面也含有较丰富的羟基、氨基和羧基等功能性官能团。此外,Fe³⁺可以猝灭CDs溶液的荧光,而Fe²⁺几乎不影响;按照CDs与Fe³⁺混合后荧光几乎消失时的浓度配比,将Fe³⁺替换成同等浓度Fe²⁺再分别加入不同浓度的H₂O₂,快速混均后测量其在320 nm激发光下的荧光发射图谱,绘制标准曲线,H₂O₂浓度在0~60 μmol·L^-1内线性关系良好,相关系数R²约为0.990 0,检测限约为0.65 μmol·L^-1。本研究结果为快速检测食品中的H₂O₂提供了一定的理论依据。

Preparation and Characterization of Chitosan-Based Carbon Dots and Its Application in Hydrogen Peroxide Analysis

To prepare a fluorescence sensor for cocoa analysis of H₂O₂, chitosan and dl-tartaric acid were used as precursors to prepare novel nitrogen doped carbon quantum dots (CDs) by hydrothermal treatment, which could be used to detect the amount of hydrogen peroxide (H₂O₂) in food efficiently and conveniently. Transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FTIR) were used to analyze and characterize.The results showed that the fluorescence quantum yield of the CDs was about 5.22%, and the particle size was about 20 nm, CDs contained a graphene structure with nitrogen atoms, and its surface showed abundant functional groups such as hydroxyl amino and carboxyl groups. In addition, Fe³⁺ can quench the fluorescence of CDs solution, while Fe²⁺ had almost no effect on CDs. According to the concentration ratio of CDs and Fe³⁺ when the fluorescence almost disappeared after mixing, then Fe³⁺ replaced by Fe²⁺ at the same concentration, and then H₂O₂ of different concentrations was added. After the rapid and uniform mixing, the fluorescence emission spectrum under the excitation light at 320 nm was measured and the standard curve was obtained with a linear relationship of H₂O₂ concentration at 0-60 nm, and the correlation coefficient called R² was about 0.990 0, with the detection limit about 0.65 nm.