基于氮、磷共掺杂碳点的荧光传感器构筑及对汞离子的高效分析

Construction of fluorescence sensor based on nitrogen and phosphorus co-doped carbon dots and the efficient analysis of mercury ion

摘要

以柠檬酸铵和磷酸胍为前驱体,利用简便的一步水热法制备了氮、磷共掺杂荧光碳点(N,P-CDs).采用傅里叶变换红外光谱、X射线光电子能谱、X射线衍射仪、透射电子显微镜、紫外-可见吸收光谱和荧光光谱对其结构、形貌和光学性质进行了表征.N,P-CDs碳点分散性好,平均粒径为2.5nm,表面含有氨基、羟基、羧基等官能团,荧光稳定性好.基于静态猝灭机制,建立了灵敏检测黄河流域河南段环境中汞离子(Hg²⁺)的新方法.Hg²⁺浓度在0.05~12.50μmol/L范围内与其荧光猝灭率呈现良好的线性关系,方法的检出限为9.50nmol/L;该方法成功用于黄河流域河南段水样和土样中Hg²⁺的分析,样品的加标回收率为96.8%~104.8%.所构筑的荧光传感器为环境中Hg²⁺的高效分析提供了一个简便快速的新方法.

Abstract

Nitrogen and phosphorus co-doped fluorescent carbon dots (N,P-CDs) were prepared by using ammonium citrate and guanidine phosphate as the precursors through a simple one-step hydrothermal method. The structure, morphology and optical properties of N,P-CDs were well characterized by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, X-ray diffractomer, transmission electron microscopy, Ultraviolet-visible (UV-vis) absorption spectroscopy, and fluorescence spectroscopy. The mean particle diameter of N,P-CDs was 2.5nm with good dispersion. There were amino, hydroxyl, carboxyl groups on the N,P-CDs surface and the N,P-CDs possessed excellent fluorescence stability. A novel approach was constructed for sensitive detection of mercury ion in environment based on the static quenching mechanism. There was a good linear relationship between the quenching effect of the N,P-CDs and the concentration of Hg ²⁺ in the range of 0.05-12.50μmol/L, and the detection limit was 9.50nmol/L. The method had been successfully employed to measure Hg ²⁺ in environmental water and soil samples from the Henan section of the Yellow River Basin, and the recoveries ranged from 96.8% to 104.8%. The constructed fluorescent sensor offered a simple and rapid method for efficiently sensing Hg ²⁺ in environmental samples.

关键词

氮、磷共掺杂碳点 / 荧光传感器 / 汞离子 / 静态猝灭

Key words

nitrogen and phosphorus co-doped carbon dots / fluorescent sensor / Hg ²⁺ / static quenching

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基金资助

国家自然科学基金(22106039)

河南省高等学校青年骨干教师培养计划(2025GGJS032)