纳米金探针检测Hg 2+离子

利用Hg2＋的核酸适体修饰纳米金形成探针建立了一种定量检测Hg2＋离子的方法. Hg2＋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Hg2＋离子存在时, 由于适体与纳米金的吸附作用小于适体与Hg2＋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520 nm红移至620 nm. 在优化条件下, 吸光度的比值(A620/A520)与Hg2＋离子浓度在5.0×10－9～7.2×10－7 mol&;#8226;L－1范围内呈线性关系, 检测限可达3.3×10－10 mol&;#8226;L－1. 研究了K＋, Ca2＋等常见离子的干扰, 结果表明该方法具有良好的选择性.

Detection of Hg 2+ Using Gold Nanoparticle Probes

A method was developed for Hg2＋ quantitative determination using the Hg2＋ 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 (Hg2＋) and the aptamer. So if the proper Hg2＋ 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 Hg2＋, the concentrations of NaCl and aptamer were optimized, and the appropriate pH was chosen. Under optimal conditions, the absorption ratio A620/A520 was proportional to the concentration of Hg2+ in the range of 5.0×10－9 to 7.2×10－7 mol&;#8226;L－1 and the detection limit was 3.3×10－10 mol&;#8226;L－1. Interferences from selected inorganic ions were investigated and the proposed method was simple and sensitive.