新型荧光碳点的制备及其在微量金属离子测定中的应用

碳点(CD)具有粒径小、抗光漂白性好、荧光稳定性高、发射光谱可调、表面易功能化、毒性低及生物相容性好等优点,已在催化、生物成像、药物传递、荧光检测、光电子器件等方面得到了广泛的应用。近年来,利用不同原料制备高性能荧光CD的合成方法备受关注。此外,通过CD直接与目标分析物相互作用,特异性配体修饰后的CD与目标分析物相互作用、CD与其他物质形成复合物后与目标分析物相互作用构建荧光探针,并将其用于微量金属离子的检测得到了迅速发展和广泛应用。本文阐述了CD的光学性质和合成原料,对其常用的自上而下法和自下而上法两类合成方法的过程及特点进行了总结。在此基础上,详细评述了基于CD与目标分析物的三种相互作用方式所构建的荧光探针在测定Fe^3+、Zn^2+、Cu^2+等具有生化作用的离子和Hg^2+、As^3+、Pb^2+、Cr^6+、Cd^2+等重金属离子的应用进展。本文指出,深入研究检测机理,发展新型检测模式,针对特定金属离子和样品组成设计构建荧光探针,建立可用于复杂样品的分析方法是开展构建新型CD荧光探针所面临的挑战和发展方向。

A Review of the Preparation of Novel Fluorescent Carbon Dot and Its Application for the Determination of Trace Metal Ions

BACKGROUND: Owing to their small particle size, good stability against photobleaching, high fluorescence stability, tunable fluorescence emission, easy surface functionalization, low toxicity and excellent biocompatibility, carbon dot (CD) has been widely applied in many fields including catalyst, cell imaging, drug delivery, fluorescence detection and photoelectronic devices. In recent years, synthetic methods for preparing high-performance fluorescent CD using different raw materials have attracted much attention. In addition, detection of trace metal ions by a fluorescent probe has been rapidly developed and widely used. The fluorescent probe can be constructed thus:the CD directly interact with the target analyte, the CD modified by the specific ligand interact with the target analyte, and the CD forming a complex with other substances interact with the target analyte.
OBJECTIVES: To provide references for researchers to synthesize CD and construct fluorescent probes based on CD for the determination of trace metal ions in complex samples.
METHODS: The optical properties and synthetic raw materials of CD were described. The process and characteristics of the commonly used top-down and bottom-up methods were summarized. The application progress of fluorescent probes constructed by the three interaction modes between CD and target analytes for the determination of biochemical reaction ions, Fe³⁺, Zn²⁺ and Cu²⁺, and other heavy metal ions such as Hg²⁺, As³⁺, Pb²⁺, Cr⁶⁺ and Cd²⁺ were reviewed.
RESULTS: Different raw materials had been utilized for synthesizing CD with different properties. The prepared CD were used to construct fluorescent probes for the determination of micro metal ions with high selectivity and sensitivity.
CONCLUSIONS: Further research on the determination mechanisms, development of new detection modes, construction of fluorescent probes for specific metal ions and sample components, and establishment of analytical methods, which can be applied to complex samples are the challenges and development orientation of the fluorescent probes based on CD.