基于双荧光基团分子信标对水体中铅离子(Ⅱ)的检测

Detection of lead(Ⅱ)in water using a dual-fluorophore molecular beacon

为了建立一种快速、准确地测量水体中铅(Pb)离子含量的方法,利用两个荧光基团6-羧基荧光素(6-Carboxy fluorescein group,FAM)和5-羧基四甲基罗丹明(5-Carboxytetramethylrhodamine,TAMRA),结合Pb离子(Ⅱ)的核酸适配体,构建了一种特殊的能特异性识别Pb^2+的双荧光基团分子信标。根据分子信标与Pb^2+结合后FAM与TAMRA总荧光强度的变化,建立了对水体中Pb^2+高灵敏的双色荧光定量检测方法。结果表明,在优化的条件下,FAM和TAMRA的总荧光强度(ΔIT)与Pb^2+的浓度(C)在8×10^-10~4×10^-8mol·L^-1范围内呈现良好的线性关系,其拟合的回归方程为ΔIT=3.052 C+13.129(R^2=0.9987),方法的检出限为1.5×10^-10mol·L^-1(3σ,n=9)。研究表明,本实验利用Pb^2+的适配体及两个荧光基团FAM与TAMRA构建的双荧光基团分子信标能特异性地识别水体中的Pb^2+,基于分子信标所建立的分析方法精密度好、准确度高,能很好地应用于水样品中Pb^2+的定量检测。

To develop a rapid and accurate method of measuring Pb^2+in water sources,a Pb^2+-specific dual-fluorophore molecular beacon(MB)was constructed using two fluorophores(FAM and TAMRA)and the nucleic acid aptamer of Pb^2+.A highly sensitive dual-color fluorescence quantitative detection method for Pb^2+in waterwas developed based on changes in the total fluorescence intensity of FAM and TAMRA after the molecular beacon and Pb^2+were combined.The results showed that the total fluorescence intensity(ΔIT)of FAM and TAMRA exhibited a good linear relationship with Pb^2+concentrations(C)ranging from 8×10^-10 to 4×10^-8 mol·L^-1 under optimized conditions.The fitted regression equation wasΔIT=3.052C+13.129(R^2=0.9987),and the detection limit of the method was 1.5×10^-10 mol·L^-1(3σ,n=9).The results of this study indicate that the constructed dual-fluorophore molecular beacon can specifically recognize Pb^2+in water sources with high precision and accuracy and can therefore be applied in quantitative detection of Pb^2+in water.