中文摘要：

基于Hg2＋与DNA中胸腺嘧啶（T）结合的高度特异性和DNA铜纳米簇的荧光增强性质,构建了一种简便、灵敏检测汞离子的新方法.当Hg2＋存在时,聚T单链DNA（P1）通过T-Hg2＋-T特异性结合形成双链DNA,Cu2＋经抗坏血酸钠还原后生成的中间体Cu＋与双链DNA螺旋结构间的氢键部分有强的结合力,促使Cu0附着聚集在双链DNA上形成铜纳米簇,导致体系荧光增强,从而实现对汞离子的高灵敏检测.体系荧光强度与Hg2＋浓度的对数值成正比,对Hg2＋检测的线性范围为1.0 nmol/L-10μmol/L,检出限达0.4 nmol/L,对湖水样品中Hg2＋检测的回收率达到97.2%-106.6%.与传统方法相比,该方法具有无需标记、检出限低及选择性好等优点,可用于环境水体中汞离子的测定.

英文摘要：

A rapid sensitive fluorescent sensor was developed for Hg（ Ⅱ） ions detection based on the specific thymine-Hg2＋-thymine structure and photoluminescent property of DNA copper nanoclusters. Upon the addition of Hg2＋,poly thymine single strand DNA（ P1） is transformed into double strand DNA through the formation of T-Hg2＋-T configuration. Sodium ascorbate is effective to reduce Cu2＋to Cu0,and this reduction process is accompanied by formation of intermediate Cu＋. However,Cu＋has a strong binding site within hydrogen-bonding moieties in the helix of ds DNA which facilating Cu0 gathered in ds DNA to form stronger fluorescent copper nanoclusters than ss DNA copper nanoclusters,and these changes in fluorescence intensity of DNA-Cu NCs are allowed for sensitive analysis of Hg（ Ⅱ） ions. Satisfactory linear relationship and detection limit were obtained. The resulting calibration plots exhibited good linear correlations in the range from 1. 0 nmol/L to10 μmol/L for Hg（ Ⅱ） ions,and the detection limits of Hg（ Ⅱ） ions was 0. 4 nmol/L. The proposed method was highly selective and other metal ions have no interfering effects on the determination. Moreover,satisfactory results were obtained while the proposed method was applied to determination of Hg2＋in real lake samples.