基于氮掺杂碳量子点的荧光微球制备和Fe3+检测

分别以尿素、氨水、二乙烯三胺、多乙烯多胺为氮源，绿色廉价的白菜为碳源，采用水热法合成氮掺杂的蓝色荧光碳量子点，结果表明多乙烯多胺氮掺杂碳量子点（NCDs）荧光量子产率最高为53.3%。然后将NCDs作为荧光探针应用于荧光微球制备和Fe³⁺检测方面，以三聚氰胺甲醛（MF）为载体，合成了氨基化MF荧光微球；基于Fe³⁺对NCDs良好的荧光猝灭效应，建立了一种荧光测定Fe³⁺的方法，并对NCDs和MF荧光微球的结构和性能进行表征。结果表明，NCDs的荧光性能得到了显著的改善；MF荧光微球单分散性好、荧光性能好且稳定，在生物医学领域方面有重要的应用价值；NCDs对Fe³⁺具有单一选择性，Fe³⁺浓度在0~2μmol/L内与NCDs的荧光猝灭程度呈良好的线性关系（R²=0.9945），检出限为0.035μmol/L。将该体系应用于实际水样中Fe³⁺的测定，相对标准偏差（RSD，n=6）在1.42%~3.02%内，加标回收率在98.7%~104.5%之间。该体系对Fe³⁺检测灵敏性好、选择性高以及抗干扰性强，在离子分析检测方面有潜在的应用前景。

Preparation of fluorescent microspheres and their detection of Fe3+ based on nitrogen doped carbon quantum dots

A hydrothermal decomposition method was developed for the synthesis of blue fluorescence nitrogen doped carbon dots (NCDs) by using cabbage juice as the carbon source and using urea, ammonia, diethylenetriamine and poly ethylene polyamine (PP) separately as the nitrogen source. The obtained fluorescence quantum yield of polyethylene polyamine doped carbon quantum dots (NCDs) was 53.3%. NCDs were used as fluorescent probes for the preparation of fluorescent microspheres and the detection of Fe³⁺. Melamine formaldehyde (MF) fluorescent microspheres with amino groups were synthesized with MF as the carrier. Due to the fluorescence quenching of NCDs by Fe³⁺, a method based on sensitive and selective fluorescent probe was developed for detecting Fe³⁺. The structure and properties of NCDs and the MF fluorescent microspheres were characterized. The results show that the fluorescence properties of the NCDs were significantly improved compared with CDs, and MF fluorescent microspheres have good dispersity and stability and high fluorescence intensity, and therefore it has important application value in the field of biomedicine; NCDs have single selectivity to iron ions, and the fluorescence quenching ratio of NCDs shows a good linear relationship with the concentration of Fe³⁺ in the range from 0 to 2×10^-6mol/L (R²=0.9945). The detection limit is 0.035×10^-6mol/L. The NCDs may be applied to the measurement of Fe³⁺ in water samples, and the relative standard deviation (RSD, n=6) is within 1.42%-3.02% with the recovery rate between 98.7%-104.5%. The system has good sensitivity, high selectivity and strong anti-interference for the detection of Fe³⁺, thus it has potential application prospects in the field of ion analysis and detection.