摘要
以巯基乙酸为修饰剂,水相合成量子产率高达75%的CdTe/CdS核壳型量子点,建立了以CdTe/CdS QDs作为能量供体,罗丹明B作为能量受体组成的荧光共振能量转移体系。在此基础上,以CdTe/CdS-罗丹明B为荧光探针,荧光共振能量转移猝灭为理论基础,设计出一种检测Pb2+含量的方法。在0～9.62×10-11 mol/L的范围内线形良好,相关系数r为0.9975。采用紫外-可见、荧光光谱法研究了CdTe/CdS-RhB体系与Pb2+的相互作用。由Stern-Volmer方程和双倒数曲线Lineweaver-Burk方程获得了反应的动态猝灭常数与双分子猝灭速率常数,并得出了不同温度下两者相互作用的结合常数、结合位点数,从而判断出其作用机理既存在动态猝灭又存在静态猝灭,以静态猝灭为主。并利用Van’t Hoff方程计算出不同温度下(293,310和318 K)的热力学参数:焓变、吉布斯自由能变化和熵变。通过计算结果对CdTe/CdS-罗丹明B体系与Pb2+反应的作用力类型做出了推断,两者之间的作用力主要为疏水作用引起的、自发的、熵驱动过程。
The water-soluble CdTe/CdS core-shell quantum dots （QDs） with a high quantum yield up to 75% were synthesized using thioglycolic acid （TGA） as stabilizer. The optical properties of CdTe/CdS QDs prepared under the optimized conditions were performed via UV-Vis spectroscopy, and fluorescence spectroscopy. Here, we present a fast, ultra-sensitive and highly selective platform by utilizing the CdTe/CdS QDs-rhodamine B system as Pb^2＋ fluorescent probes based on the fluorescence quenching theory. The extent of fluorescence quenching was linearly proportional to the trace concentration of Pb^2＋ from 0 to 9.62 × 10^-11 mol/L with a correlation coefficient of 0. 9975. According to Stern Volmer equation and Lineweaver Burk equation, the quenching constant was obtained. The binding constant and binding site number at different temperatures were calculated. It is confirmed that the quenching mechanism between CdTe/CdS-rhodamine B and Pb2. is both dynamic and static quenching, and dominated by the static quenching. The corresponding thermodynamic parameters enthalpy change （△H）, Gibbs energy change （△G） and entropy change （AS） were calculated at different temperatures （293, 310 and 318 K） according to the van＇t Hoff equation, with indicated that the interactions were spontaneous and entropically driven process, and hydrophobic forces played major roles in the binding of Pb^2＋ to CdTe/CdS- rhodamine B.
出处
《分析试验室》
CAS
CSCD
北大核心
2011年第11期37-42,共6页
Chinese Journal of Analysis Laboratory
基金
国家自然科学基金(20975050)
江苏省"六大人才高峰"项目资助
