镊子型dsDNA稳定的纳米金光度法快速检测Hg^(2+)的研究  

Rapid Detection of Mercury(Ⅱ) Based on Hg^(2+)-DNA Complexes Inducing the Aggregation of Gold Nanoparticles

作　　者：王云香[1] 薄红艳[1] 蔺凯[1] 王晓[1] 高强[1] 

机构地区：[1]陕西师范大学化学与材料科学学院陕西省生命分析重点实验室,陕西西安710062

出　　处：《分析测试学报》2011年第7期804-807,812,共5页Journal of Instrumental Analysis

基　　金：国家自然科学青年基金资助项目(20805029)

摘　　要：利用Hg2+对胸腺嘧啶(T)T-T错配的特异性结合,建立了一种利用盐诱导金纳米粒子聚集的比色定量检测Hg2+离子的方法。设计了一种镊子型dsDNA,其一半为互补碱基形成的双螺旋结构,另一半为T-T错配。错配部分保持单链状态吸附在纳米金表面,使纳米金的稳定性增强,抑制盐诱导的纳米金团聚。当存在Hg2+时,"T-Hg2+-T"结构的形成导致错配部分形成双链,纳米金去保护在盐诱导下发生团聚。溶液颜色由红变蓝,紫外-可见光谱的最大吸收峰由520 nm红移至620 nm。在优化条件下,吸光度的比值(A620/A520)与Hg2+的浓度在5.0×10-8~5.0×10-7mol/L范围内呈良好线性关系,检出限达3.0×10-8mol/L。研究了Ca2+、Mg2+等常见离子的干扰,结果表明该方法具有良好的选择性。由于镊子型dsDNA的独特结构,使得纳米金的团聚在Hg2+加入后的数秒内发生,1 min内达到平衡,大大加快了分析速度。A simple and rapid colorimetric method was developed for the detection of Hg2＋ based on the specific thymine T-Hg2＋-T structure and gold nanoparticles.A tweezers-like duplex DNA,containing 9 T-T mismatches in the end,was designed.The mismatched thymines in the tweezers-like dsDNA could not form helix structure,which could attach to AuNPs and effectively prevent AuNPs from salt induced aggregation.While in the presence of Hg2＋ ions,the T-Hg2＋-T coordinations would lead these thymines to form the structures of helix.The AuNPs were less well-protected thus aggregated at the same salt concentration,accompanied by color changing from red to blue.The maximum absorption wavelength of AuNPs solution would change from 520 nm to 620 nm.Under the optimal conditions,the absorption ratio A620/A520 was proportional to Hg2＋ concentration in the range of 5.0×10-8-5.0×10-7 mol/L with a detection limit of 3.0×10-8 mol/L.The interferences from selected inorganic ions were investigated.The result indicated that the sensor showed a good selectivity for Hg2＋,and other metal ions（e.g.Ca2＋,Mg2＋） had no significant interferences.The proposed method was simple and rapid,and could be used in the detection of Hg2＋ within 1 min.

关 键 词：汞离子 T-Hg2+-T 纳米金 光度法 快速检测 

分 类 号：O561.3[理学—原子与分子物理] O614.243[理学—物理]