新型汞离子CQDs-CuNCs比率荧光探针的构建及在螃蟹中的应用

doi:10.3964/j.issn.1000-0593(2019)12-3925-07

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摘要：汞是一种典型的低剂量高毒性物质，广泛存在于环境和水体中，可通过食物链传递并累积，从而对人体造成危害。因此，准确快速的监测食品中汞离子（Hg²⁺）含量对于保障食品安全具有重要意义。目前，常用的Hg²⁺检测方法包括液相色谱-原子荧光光谱法（LC-AFS）、电感耦合等离子质谱法（ICP-MS）、电化学法和荧光分析法。比率型荧光探针具有双发射荧光特性，其中内置校准功能可降低因探针浓度和各种环境因素产生的检测误差，可以有效的克服单发射荧光探针的不足。本研究提出了基于碳量子点（CQDs）和铜纳米簇（CuNCs）的新型比率型荧光探针用于螃蟹中Hg²⁺的快速检测。主要研究内容和结果如下：（1）CQDs-CuNCs复合体系的制备。以蔗糖为碳源，聚乙二醇为钝化剂，通过微波介导法合成CQDs；以抗坏血酸为还原剂和稳定剂通过水热法合成CuNCs，后通过自组装制成CQDs-CuNCs复合体系。（2）CQDs-CuNCs复合体系的表征。利用高倍透射电子显微镜（HRTEM）、紫外-可见吸收光谱（UV-Vis）、荧光光谱（FL）和傅里叶变换红外光谱（FTIR）对CQDs-CuNCs复合体系表征，结果显示，该研究成功合成了具有双发射特性的CQDs-CuNCs比率型荧光探针。（3）CQDs-CuNCs复合体系的稳定性测试。将CQDs-CuNCs比率型探针与传统的单通道CuNCs探针的稳定性进行对比。结果表明，当探针浓度漂移和测量温度波动时，CQDs-CuNCs比率型探针比单发射的CuNCs抗干扰能力更强，稳定性更高。（4）CQDs-CuNCs复合体系对Hg²⁺的检测。当Hg²⁺存在时，复合体系中的CuNCs发生团聚，而CQDs基本不受影响，导致443 nm处的CuNCs荧光猝灭而545 nm处的CQDs荧光强度几乎不变。依据荧光强度的比值（I_{443 nm}/I_{545 nm}）与Hg²⁺浓度的关系实现定量检测。在对标准Hg²⁺检测时，CQDs-CuNCs复合体系的I_{443 nm}/I_{545 nm}和单发射CuNCs的猝灭率与Hg²⁺浓度（0.1～12 μmol·L^-1）均呈现良好的线性关系，相关系数分别达到0.994 7和0.991 6，检测限（3σ/S）分别为2.83和3.62 nmol·L^-1。在螃蟹样品检测中，CQDs-CuNCs比率型探针和单发射的CuNCs得到回收率分别为102.5%~105.4%和104.2%~112.5%，说明CQDs-CuNCs复合体系比单发射CuNCs对Hg²⁺具有更高的灵敏性和稳定性。以上结果表明，本研究所构建的CQDs-CuNCs比率型荧光探针能够用于食品中Hg²⁺的快速、准确检测。

关键词：铜纳米簇；碳量子点；Hg²⁺；比率型荧光探针

Abstract：Mercury is a typical low-dose and high-toxic substance, which widely exists in the environment and water. It is transmitted and accumulated through the food chain, which is easy to cause harm to human body. Therefore, accurate and rapid monitoring of Hg²⁺ content is of great significance for ensuring food safety. At present, there are many techniques to detect mercury ions such as high performance liquid chromatography atomic fluorescence spectrometry (LC-AFS), inductive coupled plasmamass spectroscopy (ICP-MS), electrochemical methods and fluorescence analysis methods. Ratio fluorescence probe has dual emission fluorescence characteristics. The built-in calibration function can reduce the detection errors caused by probe concentration and various environmental factors, and effectively overcome the shortcomings of single emission fluorescence probe. A novel ratio fluorescent probe based on carbon quantum dots (CQDs) and copper nanoclusters (CuNCs) was proposed for the rapid detection of Hg²⁺ in crabs. The main research contents and results are as follows: (1) The preparation of CQDs-CuNCs composite system, CQDs were synthesized by microwave-mediated method with sucrose as carbon source and polyethylene glycol as passivator; CuNCs were synthesized by hydrothermal method using ascorbic acid as reductant and stabilizer, and then self-assembled into CQDs-CuNCs composite system. (2) Characterization of CQDs-CuNCs composite system. The CQDs-CuNCs composite system was characterized by high power transmission electron microscopy (HRTEM), ultraviolet-visible absorption spectroscopy (UV-Vis), fluorescence spectroscopy (FL) and Fourier transform infrared spectroscopy (FTIR). The results show that the CQDs-CuNCs ratio fluorescent probe with dual emission characteristics has been successfully synthesized. (3) The stability of CQDs-CuNCs composite system was tested. The stability of CQDs-CuNCs ratio probe was compared with that of traditional single-channel CuNCs probe. The results show that the migration of CQDs-CuNCs ratio probes is stronger and stabler than that of single-emitted CuNCs when the probe concentration drift and temperature fluctuation are measured. (4) The CQDs-CuNCs composite system detects Hg²⁺. When Hg²⁺ exists, the CuNCs in the composite system will agglomerate, but CQDs will not be affected, resulting in the fluorescence quenching of CuNCs at 443 nm and the fluorescence intensity of CQDs at 545 nm almost unchanged. Quantitative detection of Hg²⁺ was realized based on the relationship between the ratio of fluorescence intensity (I_{443 nm}/I_{545 nm}) and the concentration of Hg²⁺. In the standard sample detection, the quenching rate of CQDs-CuNCs composite system at I_{443 nm}/I_{545 nm} and single-emission CuNCs has a good linear relationship with Hg²⁺ (0.1～12 μmol·L^-1), the correlation coefficients are 0.994 7 and 0.991 6, and the detection limits (3σ/S) are 2.83 and 3.62 nmol·L^-1, respectively. In crab sample detection, the recoveries of CQDs-CuNCs ratio probe and single-emission CuNCs were 102.5%~105.4% and 104.2%~112.5%, respectively. The results show that the CQDs-CuNCs composite system has higher sensitivity and recovery to Hg²⁺ than single-emission CuNCs. The CQDs-CuNCs ratio fluorescent probe constructed in this study can be used for rapid and accurate detection of Hg²⁺ in food.

Key words：Copper nanoclusters; Carbon quantum dots; Mercury ions; Ratiometric fluorescence probe

收稿日期: 2018-11-27 修订日期: 2019-03-12

中图分类号:

O657.3

基金资助: 国家重点研发计划项目（2018YFD0701001），国家自然科学基金项目（31772073，31671844），江苏省重点研发计划项目（BE2016306），江苏省六大人才高峰（GDZB-016）资助

通讯作者: 邹小波 E-mail: zou_xiaobo@ujs.edu.cn

作者简介: 石吉勇，1984年生，江苏大学食品与生物工程学院副教授 e-mail：shi_jiyong@ujs.edu.cn

引用本文:

石吉勇，李文亭，胡雪桃，史永强，邹小波. 新型汞离子CQDs-CuNCs比率荧光探针的构建及在螃蟹中的应用[J]. 光谱学与光谱分析, 2019, 39(12): 3925-3931.
SHI Ji-yong, LI Wen-ting, HU Xue-tao, SHI Yong-qiang, ZOU Xiao-bo. A New Ratiometric Fluorescence Probe Based on CuNCs and CQDs and Its Application in the Detection of Hg²⁺. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2019, 39(12): 3925-3931.

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