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利用Hg2+与胸腺嘧啶(T)结合的高度特异性,结合CdTe量子点(QDs)和Au纳米粒子(AuNPs)进行双信号分子标记,建立了一种Hg2+定量检测方法。利用ssDNA对CdTe QDs和AuNPs进行连接,利用T碱基与Hg2+形成“T-Hg2+-T”结构诱导单链DNA折叠和2个单链形成双链引起CdTe与AuNPs聚集,此时溶液颜色发生变化,由红变蓝;并且发生荧光猝灭,产生双信号。在最优条件下,以荧光信号为例,荧光猝灭程度与Hg2+浓度的对数值在10-3~10.0μmol/L范围呈良好线性关系,线性回归方程ΔI=164.66-130.68lgc(μmol/L),检出限计算为0.4nmol/L。该方法成功用于水样中汞的测定,获得令人满意的结果。
The Hg2 + quantitative detection method was established based on the high specificity of Hg2 + binding to thymine (T) and the double-labeling of CdTe quantum dots (QDs) and Au nanoparticles (AuNPs). CdTe QDs and AuNPs were connected by ssDNA, and the “T-Hg2 + -T” structure was formed by T bases and Hg2 + to induce single-stranded DNA folding and double-stranded double stranded DNA to cause CdTe and AuNPs to aggregate. At this time, the solution color Changes from red to blue; and fluorescence quenching, resulting in a double signal. Under the optimal conditions, taking the fluorescence signal as an example, the fluorescence quenching degree has a good linear relationship with the logarithm of Hg2 + concentration in the range of 10-3 ~ 10.0μmol / L, the linear regression equation ΔI = 164.66-130.68lgc (μmol / L ), The detection limit calculated as 0.4nmol / L. The method has been successfully applied to the determination of mercury in water samples with satisfactory results.