大肠杆菌一步水热法制备氮掺杂碳量子点及其在铁离子检测中应用

One-step Hydrothermal Synthesis of Nitrogen-doped Carbon Quantum Dots with Escherichia Coli for Selective Detection of Ferric Ion

以大肠杆菌沉淀物为前驱体,采用水热法(180℃)一步合成水溶性好、pH稳定性和抗盐性突出的氮掺杂碳量子点(N-CQDs)。通过透射电子显微镜、动态光散射和傅立叶红外光谱对N-CQDs进行了表征,N-CQDs呈圆球状,粒径均一,大小4.1 nm,分散良好,表面含大量亲水基团;采用紫外-可见吸收光谱和荧光光谱考察其光学性能,结果表明, Fe^(3+)离子可对N-CQDs选择性荧光猝灭,在0.58 nmol/L～100μmol/L浓度范围内,荧光猝灭程度与Fe^(3+)浓度呈良好的线性关系,检出限为0.58 nmol/L,回收率为93.9%～108.7%;同时考察了pH值、含盐量、金属离子共存对Fe^(3+)测定的干扰,结果表明,本方法适用于含盐量较高、pH值变化范围较大、共存金属离子多样的近海海水中Fe^(3+)的选择性荧光检测。

Nitrogen-doped carbon quantum dots (N-CQDs) with good water solubility, pH stability and salt tolerance were synthesized by hydrothermal method (180℃) with Escherichia coli as precursor. The structure of N-CQD was characterized by transmission electron microscopy, dynamic light scattering, and Fourier transform infrared spectroscopy. The results showed that the particle size was uniform with a diameter of 4.1 nm , the dispersibility was good, and the surface contained a large amount of hydrophilic groups. UV-visible absorption and fluorescence spectra were used to study optical properties, and it was found that Fe 3+ could selectively quench the N-CQDs fluorescence. In the concentration range of 0.58 nmol/L-100 μmol/L, the quenching degree had a good linear relationship with the concentration of Fe^3+ ion. The detection limit was 0.58nmol/L , and the recoveries were 93.9%-108.7%. At the same time, the interference of pH, salt content and coexistence metal ion on Fe 3+ determination was studied. The results showed that the method was especially suitable for selective fluorescent detection of Fe 3+ in offshore seawater with high salt content, large range of pH and diverse metal ions.