Functional preserving carbon dots-based fluorescent probe for mercury (II) ions sensing in herbal medicines via coordination and electron transfer

• Published in: Analytica chimica acta 2018-12, Vol.1035, p.203-210
• Main Authors: He, Jia Hui, Cheng, Yun Ying, Yang, Tong, Zou, Hong Yan, Huang, Cheng Zhi
• Format: Article
• Language: English
• Subjects: Carbon; Carbon - chemistry; Carbon dots; Citric Acid - chemistry; Complex compounds; Core-shell structure; Electron transfer; Electron Transport; Fluorescence; Fluorescent Dyes - chemistry; Fluorescent indicators; Fluorescent probe; Functional groups; Heavy metals; Herbal medicine; Herbal medicines; Hg2; Mercury; Mercury (metal); Mercury - analysis; Mercury - metabolism; Plant Preparations - analysis; Quality control; Quantum Dots - chemistry; Quantum Dots - metabolism; Sensitivity and Specificity; Spectrometry, Fluorescence - methods; Spermine - chemistry; Toxicity
• ISSN: 0003-2670; 1873-4324
• DOI: 10.1016/j.aca.2018.06.053

Mercury ions (Hg2+) are one of the compulsory items in the quality control of herbal medicines for its serious toxicity to human health. Highly selective and sensitive Hg2+ detection, especially in complex real samples, is still challenging. In this work, Fluorescent (FL) carbon dots (CDs) with a core-shell structures composed of the crystalline core of stacked sp2-hybridized carbon layers and the shell of functional groups on the periphery of carbon layers are facilely prepared through a one-step hydrothermal synthetic route. They can specifically interact with Hg2+ in aqueous medium to form aggregates, during which coordination of carboxyl functional groups on the surface of CDs with Hg2+ occurred, which facilitated electron transfer from the CDs to Hg2+. As a result, fluorescence of the CDs was quenched with a high efficiency, making the detection of Hg2+ highly sensitive with the limit of determination (LOD) of 2.2 nM (3σ). With that, detection of Hg2+ in the complex compound herbal medicines samples with highly reproducible results has been successfully realized by using the as-prepared CDs, showing that fluorescent CDs-based probe may have great potential in the quality controls of heavy metals for pharmaceutical analysis. [Display omitted] •The CDs of abundant carboxyl functional groups could respond specially to the Hg2+.•The binding mechanism of Hg2+ with CDs is well studied.•The visual detection of Hg2+ in the complex herbal medicines samples has been successfully realized.