中文摘要：

利用Hg^2＋的核酸适体修饰纳米金形成探针建立了一种定量检测Hg^2＋离子的方法．Hg^2＋适体吸附在纳米金表面，使纳米金的稳定性增强，抑制氯化钠对纳米金的团聚作用．溶液中有Hg^2＋离子存在时，由于适体与纳米金的吸附作用小于适体与Hg^2＋离子的亲和作用，纳米金失去适体保护在氯化钠作用下发生团聚．溶液颜色由红变蓝，紫外-可见光谱最大吸收峰由520nm红移至620nm．在优化条件下，吸光度的比值（A620/A520）与Hg^2＋离子浓度在5．0×10^-9～7．2×10^-7mol·L^-1范围内呈线性关系，检测限可达3．3×10^-10mol·L^-1．研究了K^＋，Ca^2＋等常见离子的干扰，结果表明该方法具有良好的选择性．

英文摘要：

A method was developed for Hg^2＋ quantitative determination using the Hg^2＋ aptamer to modify gold nanoparticles （AuNP）. The aptamer would adsorb onto the AuNP and help to enhance the AuNP stability against salt-induced aggregation. But this attraction was weaker than the affinity between the target （H^g2＋） and the aptamer. So if the proper Hg^2＋ and aptamer were put into the AuNP solution, addition of salt resulted in aggregation of AuNP that led to red-to-blue color change. And the maximum absorption wavelength would change from 520 to 620 nm. Before detecting Hg^2＋, the concentrations of NaC1 and aptamer were optimized, and the appropriate pH was chosen. Under optimal conditions, the absorption ratio A620/A520 was proportional to the concentration of Hg^2＋ in the range of 5.0 × 10^-9 to 7.2 × 10^-7 mol·L^-1 and the detection limit was 3.3 × 10^-10 mol·L^-1. Interferences from selected inorganic ions were investigated and the proposed method was simple and sensitive.