双发射荧光纳米微球的制备及其用于Hg^(2+)的可视化检测

Preparation of the dual-emission fluorescent probe and its use forvisual detection of Hg^(2+)

报道了一种荧光可视化检测Hg^(2+)浓度的新方法。首先通过静电相互作用直接将负电荷的CdTe/CdS量子点自组装在带正电荷异硫氰酸荧光素掺杂的二氧化硅微球(FITC-SiO_2)表面。荧光光谱显示制备的纳米复合微球(FITC-SiO_2-CdTe)同时具有FITC分子绿色及量子点红色的荧光峰。由于Hg^(2+)会与量子点表面的巯基分子结合而猝灭量子点的荧光,而对微球内部的绿色荧光无明显响应,因此可以根据量子点与FITC分子荧光强度比值的改变来检测Hg^(2+)的浓度。标准条件下,量子点与FITC分子荧光强度比值与Hg^(2+)在浓度0~15μmol/L范围内成线性关系,检测限可达0.5μmol/L。另外,随着Hg^(2+)浓度的增加,探针溶液的颜色由红色逐渐变为绿色,这说明可通过肉眼观察溶液荧光颜色的变化估算Hg^(2+)浓度。

This paper describes a new fluorescent nanoprobe for visual detection of Hg^2＋.First the near-infrared emitting CdTe/CdSquantum dots（QDs） were conjugated on the surface of fluorescein isothiocyanate（FITC）-doped silica nanoparticles through the electrostatic interaction.The obtained dual-emission fluorescent silica nanoparticle presents two peaks characteristic of FITC-doped silica cores and CdTe/CdSQDs,respectively.The fluorescence intensity ratio of CdTe/CdSQDs and FITCdoped silica cores could be used to measure precisely the concentration of Hg^2＋ because Hg^2＋ can effectively quench the red fluorescence of the QDs,whereas the inner green fluorescence remained unchanged.Under optimal conditions,the fluorescence intensity ratio decreased linearly with the concentration of Hg^2＋ ranging from 0 to 15 μmol/L and the detection limit was 0.5 μmol/L.In addition,the changes of the fluorescence colors can be used as an indicator by naked eye detection of the concentration of Hg^2＋.